bluuebunny/crossref_metadata_2025 huggingface dataset:
Case of intercostal lung hernia with hemosputum that developed after thoracoscopic lobectomy
Authors: Haneda Hiroshi , Okuda Katsuhiro , Nakanishi Ryoichi
Published: October 2018

Intercostal lung hernia is defined as a protrusion of the lung tissue through a chest wall defect. It is an uncommon condition after a lobectomy, and most cases are asymptomatic. We herein report a case of intercostal lung hernia after a thoracoscopic right upper lobectomy in a patient whose chief complaint was hemosputum. Elevated intrathoracic pressure is a major risk factor for intercostal lung hernia. In this patient, obesity and bronchial asthma were considered the causes of this disease. Three reports on intercostal lung hernia after thoracoscopic lobectomy were previously published. In three of the four lung hernia cases (including our own), right upper lobectomy had been performed, and the middle lobe was herniated. We consider right upper lobectomy to be an anatomical risk factor.
Clinical aspects and polymorphisms in the LTA, TNFA, LTB genes and association with dental implant loss
Authors: Broker Rita de Cássia , Doetzer Andrea Duarte , de Souza Cleber Machado , Alvim‐Pereira Fabiano , Alvim‐Pereira Claudia Cristina , Trevilatto Paula Cristina
Published: October 2018

Background

This study shows the relationship between host factors and environmental factors in the influence of susceptibility to loss of dental implants.

Purpose

The aim of this study was to investigate the association of clinical aspects and tag SNPs of the genes LTA, TNFA, and LTB with dental implant loss.

Materials and Methods

The subjects consisted of 244 patients, divided into two groups: control group (C)—163 individuals who did not lose any implants, being in function for at least 6 months; and study group (S)—81 individuals who had lost at least one implant. DNA was collected from saliva, and the genotypes were determined by real time PCR. Univariate and multivariate analysis were employed p < .05.

Results

After multivariate analysis, dental implant loss remained associated with the presence of teeth (p = .011), a larger amount of placed implants (p = .001), and allelle C of rs2009658 of the LTA gene (p = .006). For the other tag SNPs of these studied genes, there was no association between the groups C and S with dental implants loss.

Conclusion

Presence of teeth, number of placed implants and allele C of rs2009658 of LTA gene were associated with implant loss.
‘Humanitarianized’ Development? Anti‐trafficking Reconfigured
Authors: Molland Sverre
Published: October 2018

Over the past three decades humanitarianism has broadened considerably in scope. Humanitarian aid agencies have increasingly moved beyond a traditionally narrow concern with immediate relief aid to engage the wider implications of their work. Humanitarian arguments have also become central to policy legitimation in a range of contexts outside the humanitarian aid sector. By contrast, this article, based on research into anti‐trafficking programmes in the Mekong region of Southeast Asia, considers a case where a particular humanitarian discourse has in fact narrowed. Anti‐trafficking, once informed by development discourses of poverty reduction and long‐term well‐being of populations, has become increasingly shaped by a humanitarian emergency logic of exceptionalism. Long‐term development modalities have contracted into a zeal for the immediateness of ‘rescues’ and saving lives. By drawing attention to how development and humanitarian discourses intersect in anti‐trafficking interventions, this article explores how such shifts in legitimization and mobilization have taken place, in turn transforming actors and practices. The article will suggest that it is the different temporal registers of the two discourses — development and humanitarianism — that help account for this shift from the former to the latter.
Multilateral Trade Liberalisation and Financial Openness
Authors: Gnangnon Sèna Kimm
Published: October 2018

This article examines the effect of multilateral trade liberalisation (MTP) on financial openness (capital account openness). Results show that MTP induces higher financial openness in low‐income countries (LICs) and old industrialised countries. For other subsamples, the effect is negative and could be explained by the fact that countries that lack the requisite institutions and financial systems to derive full benefits from higher financial openness would likely limit their capital account openness while trying to maximise their benefits from opportunities offered by greater MTP. Greater multilateral cooperation on trade matters would be particularly beneficial to LICs.
Modular configuration of service elements based on the improved K‐means algorithm
Authors: Zhang Fei
Published: October 2018

To reduce the vagueness and subjectivity of customer demand in the process of product–service system design, a fuzzy semantic calculation method is proposed to obtain the importance of service demand. In addition, according to the demand of the clustering of service modules, a new clustering method is proposed to analyse discrete data based on the improved K‐means algorithm that is based on the Kruskal algorithm. According to the criterion of the service module division and its weight, the correlation coefficient between any two service activities is judged to form the comprehensive correlation coefficient matrix, and the comprehensive dissimilarity matrix can be obtained by the additive model. Then, this method calculates the minimum cost spanning tree (MCST) using the Kruskal algorithm. The different clusters of service activities with different centres can be found based on the MCST, and the edge values can be calculated by the improved K‐means algorithm. This paper uses 28 service activities of excavators. These activities can be divided into K (K = 4, 5, 6, and 7) clusters by the improved K‐means algorithm. Finally, the service element configuration model is established based on the demand weight, which is optimized by using the maximum customer satisfaction of competition.
Expectations and perceptions of politeness norms among Arabic learners and Moroccan native speakers
Authors: Hannouchi Said
Published: October 2018

This study explored the expectations that Moroccan native speakers (n = 57) and beginning‐level learners of Arabic (n = 38) held of one another regarding conformity to Moroccan cultural norms. Questionnaires and interviews were used to unpack two assumptions that shape pedagogical practices: (1) that native speakers (NSs) expect nonnative speakers (NNSs) to conform to NSs’ politeness norms; and (2) that NNSs differ from NSs in their perceptions of politeness norms. Results showed that Moroccan participants hold both an expectation of and flexibility toward learners’ conformity to politeness norms and that NNSs may not differ notably from NSs in their perceptions of politeness. The study has implications for understanding the conceptualization and development of intercultural competence and teaching the Communities goal area.
STAT1 facilitates oestrogen receptor α transcription and stimulates breast cancer cell proliferation
Authors: Hou Yingxiang , Li Xin , Li Qianhua , Xu Juntao , Yang Huijie , Xue Min , Niu Gang , Zhuo Shu , Mu Kun , Wu Gaosong , Li Xiumin , Wang Hui , Zhu Jian , Zhuang Ting
Published: October 2018

Oestrogen receptor α (ERα) is overexpressed in two‐thirds of all breast cancer cases and is involved in breast cancer development and progression. Although ERα ‐positive breast cancer can be effectively treated by endocrine therapy, endocrine resistance is an urgent clinical problem. Thus, further understanding of the underlying mechanisms involved in ERα signalling is critical in dealing with endocrine resistance in patients with breast cancer. In the present study, unbiased RNA sequence analysis was conducted between the MCF‐7 and MCF‐7 tamoxifen‐resistant (LCC2) cell lines in order to identify differentially expressed genes. The whole transcriptomic data indicated that the JAK‐STAT pathway is markedly up‐regulated, particularly the ISGF3 complex. As the critical effectors, STAT1 and IRF9 were up‐regulated 5‐ and 20‐fold, respectively, in LCC2 cells. The biological experiments indicated that STAT1 is important for ERα signalling. Depletion of STAT1 or inhibition of STAT1 function significantly decreased levels of ERα protein, ERα ‐target gene expression and cell proliferation in both the MCF‐7 and LCC2 cell lines. Chromatin immunoprecipitation revealed that ERα transcription is associated with STAT1 recruitment to the ERα promoter region, suggesting that transcriptional regulation is one mechanism by which STAT1 regulates ERα mRNA levels and ERα signalling in breast cancer cells. The present study reveals a possible endocrine‐resistant mechanism by which STAT1 modulates ERα signalling and confers tamoxifen resistance. Targeting of STAT1 is a potential treatment strategy for endocrine‐resistant breast cancers.
Plasma derived from human umbilical cord blood: Potential cell‐additive or cell‐substitute therapeutic for neurodegenerative diseases
Authors: Ehrhart Jared , Sanberg Paul R. , Garbuzova‐Davis Svitlana
Published: October 2018

Limited efficacy of current therapeutic approaches for neurodegenerative disease has led to increased interest in alternative therapies. Cord blood plasma (CBP) derived from human umbilical cord blood (hUCB) may be a potential therapeutic. Benefits ofCBPinjection into rodent models of aging or ischaemic stroke have been demonstrated, though how benefits are elicited is still unclear. The present study evaluated various factors within the same samples ofCBPand human adult blood plasma/sera (ABP/S). Also, autologousCBPeffects vs.ABP/S or foetal bovine serum supplements on mononuclear cells fromhUCB(MNC hUCB) in vitro were determined. Results showed significantly low concentrations of pro‐inflammatory cytokines (IL‐2,IL‐6,IFN‐γ, andTNF‐α) and elevated chemokineIL‐8 inCBP. Significantly higher levels ofVEGF, G‐CSF,EGFandFGF‐basic growth factors were determined inCBPvs.ABP/S. AutologousCBPmedia supplements significantly increasedMNC hUCBviability and decreased apoptotic cell activity. We are first to demonstrate the uniqueCBPcomposition of cytokines and growth factors within the sameCBPsamples derived fromhUCB. Also, our novel finding that autologousCBPpromotedMNC hUCBviability and reduced apoptotic cell death in vitro supportsCBP's potential as a sole therapeutic or cell‐additive agent in developing therapies for various neurodegenerative diseases.
Update on Aging Statistics and Geriatrics Development in China
Authors: Chen Yiyin , Kang Lin , Liu Xiaohong , Liu Youshuo
Published: October 2018

See the Reply by Li et al.
Stethoscope of the 21st century: dominant discourses of ultrasound in medical education
Authors: Feilchenfeld Zac , Kuper Ayelet , Whitehead Cynthia
Published: October 2018

Context

In recent years, point‐of‐care ultrasound (POCUS) has become a widely used clinical tool in a number of clinical specialties. In response, POCUS has been incorporated into medical curricula across the learning continuum, bolstered by enthusiastic appraisals of the technology's benefits for learners, clinicians and patients. In this project, we have sought to identify and understand the effects of dominant discourses influencing the integration of POCUS into medical education.

Methods

We conducted a Foucauldian critical discourse analysis (CDA) to identify and analyse discourses that legitimise and privilege the use of POCUS in medical education. We assembled an archive of 473 texts published between 1980 and 2017. Each article in the archive was analysed to identify frequently occurring truth statements (expressing concepts whose truths are unquestioned within particular discourses) that we used to characterise the major discourses that construct representations of POCUS in medical education.

Results

We identified three dominant discourses: (i) a visuo‐centric discourse prioritising the visual information as truth over other clinical data; (ii) a utilitarian discourse emphasising improvements in patient care; and (iii) a modernist discourse highlighting the current and future needs of clinicians in our technological world. These discourses overlap and converge; the core discursive effect makes the further elevation of POCUS in medical education, and the resulting attenuation of other curricular priorities, appear inevitable.

Conclusions

The three dominant discourses identified in this paper engender ideal conditions for the proliferation of POCUS in medical education through curricular guidelines, surveys of adherence to these guidelines and authoritative position statements. By identifying and analysing these dominant discourses, we can ask questions that do not take for granted the assumed truths underpinning the discourses, highlight potential pitfalls of proposed curricular changes and ensure these changes truly improve medical education.
Favourable renal outcomes after intravenous thrombolytic therapy for acute ischemic stroke: Clinical implication of kidney–brain axis
Authors: Chang Teng‐Hsiang , Chiu Ping‐Fang , Tsai Chun‐Chieh , Chang Chin‐Hua , Wu Chia‐Lin , Kor Chew‐Teng , Li Jhao‐Rong , Kuo Cheng‐Ling , Huang Ching‐Shan , Chu Cheng‐Chung , Lin Chih‐Ming , Chang Chia‐Chu
Published: October 2018

Aim

Recombinant tissue plasminogen activator (rt‐PA) administration is the most prevalent treatment for acute ischemic within golden time. However, the effects of rt‐PA on the kidney function in such patients remain unknown. This study determined long‐term renal outcomes in patients with acute ischemic stroke receiving systemic rt‐PA.

Methods

We enroled patients who were hospitalized for acute ischemic stroke from January 2001 to January 2017. We applied 1:2 propensity score matching to eliminate various confounding variables. We defined surrogate renal outcomes as declining of estimated glomerular filtration rate (eGFR) greater than 30% and 50%, and chronic kidney disease (CKD) with eGFR less than 60 mL/min. We then compared the 1‐year eGFR with paired t‐test in patients treated with or without rt‐PA.

Results

Overall, 343 of 1739 patients received rt‐PA within golden time. After 1:2 propensity score matching, their baseline characteristics were grouped as treated with rt‐PA (n = 235) or not (n = 394). rt‐PA‐treated patients exhibited slower renal progression, including the risk of eGFR declining greater than 30% (hazard ratio (HR), 0.72; P = 0.03), risk of declining eGFR greater than 50% (HR, 0.63; P = 0.046) and risk of CKD (HR, 0.61; P = 0.005). After 1‐year cohort, the rt‐PA group exhibited an improved renal outcome by the paired t‐test (propensity match: ΔGFR = 9.1 (95% confidence interval: 6.3, 11.8), P < 0.001 in rt‐PA group; ΔGFR = −1.1 (95% confidence interval: −2.9, 0.7), P = 0.23 in non‐rt‐PA group). In patients with eGFR less than 45 mL/min (n = 34), intracerebral haemorrhage was not reported.

Conclusion

Patients receiving rt‐PA for acute ischemic stroke exhibit favourable renal outcomes, and no increased incidence of intracerebral haemorrhage occurs in rt‐PA patients with advanced CKD.
Foreclosure Risk and Community Health: Does Social Capital Have a Protective Effect?
Authors: Daley Dorothy M. , Goerdel Holly T. , Pierce John C. , Dinsmore Renee
Published: October 2018

This study draws upon the social determinants of health framework to model and test the extent to which a community’s social capital is health protective in the face of a substantial economic shock, namely the recent foreclosure crisis. U.S. county–level data are used to analyze potential moderating effects of social capital on health given a community’s foreclosure risk. We rely upon established social capital measures for U.S counties and merge them with county level foreclosure risk scores constructed by the U.S. Department of Housing and Urban Development (HUD). While theorists suggest that social capital’s effect on health and other outcomes may be durable over time there have been few empirical tests of this. We interact established social capital indicators measured at two points in time with foreclosure risk to predict overall self‐reported health. Our results provide strong support suggesting that high levels of social capital are health protective. Communities with high levels of social capital that are facing high foreclosure risks report significantly better aggregate health outcomes than comparable communities facing the same level of foreclosure risk, but lower levels of social capital.
Social Constructions, Anticipatory Feedback Strategies, and Deceptive Public Policy
Authors: Schneider Anne L. , Ingram Helen M.
Published: October 2018

Elected leaders adopt “anticipatory feedback strategies” in designing public policies that generate support and forestall opposition. This contention is at the core of a social construction theory of feedback. Officials anticipate approval when policies allocate benefits to powerful groups socially constructed as deserving and allocate costs or punishment to groups viewed as undeserving, particularly if these groups lack political power. Designs for powerful groups that are widely viewed as unworthy provide mainly benefits in ways that are hidden from the general public who would not approve. For politically weak groups regarded as deserving, legislators generally design policies that provide promises, but not much in terms of material benefits. Often, deception will be used to protect or enhance this particular allocation pattern, including the reinforcement, perpetuation, or change in the social constructions along with the stereotypes, labels, stigma, and accompanying narratives. Using data from legislation introduced by the 2016 Arizona Legislature, we find that most policy is directed toward providing benefits to positively viewed target populations, as expected by the theory, and legislators employ deceptive feedback strategies that protect themselves. Feedback from the general public, which otherwise might be expected, may be precluded by the deceptive strategies being used.
Preservice educators’ perceptions of manipulatives: The moderating role of mathematics teaching self‐efficacy
Authors: Carbonneau Kira J. , Zhang Xue , Ardasheva Yuliya
Published: October 2018

In this study, we examine how prospective teachers perceive the efficacy of manipulatives and if these perceptions relate to their future use of manipulatives and their mathematics self‐efficacy. Survey responses from 97 preservice educators who had completed a mathematics method course indicate three essential findings. One, preservice teachers in this sample perceive manipulatives as highly effective for enhancing students’ performance, conceptual knowledge, and affect and reported high levels of the intended use of manipulatives in their future teaching. Two, both preservice teachers’ mathematics content and teaching self‐efficacies were significant negative predictors of the intended use of manipulatives. Three, the relationship between preservice educators’ perceptions and the intended use of manipulatives is dependent upon their mathematics teaching self‐efficacy.
Organizational Climate in Early Childhood Education
Authors: Veziroglu-Celik Mefharet , Yildiz Tulin Guler
Published: October 2018

Organizational climate is a concept that may affect individual behaviors, attitudes and well-being in organizational life as well as explain why some organizations are more productive, effective, innovative and successful than others. The concept has been investigated in many disciplines such as sociology, psychology, anthropology, political science, and management for years and was first considered in education at the end of the 1960s. Since then it has been researched in the field of education in many studies. In this paper, the organizational climate of early childhood centers is examined according to the opinions of early childhood teachers. The Early Childhood Work Environment Scale was used to obtain the data. Participants were a total of 214 teachers who work in public early childhood centers in an urban school district of Turkey. Teachers reported on their opinions of ten components of organizational climate: Collegiality, professional development, director support, clarity, reward system, decision making, goal consensus, task orientation, physical setting, and innovativeness. Results showed that collegiality is at the highest level among the components and the most negative opinion was expressed for the professional development component of the organizational climate. The findings are discussed in the light of the related literature. Suggestions for educators, researchers and decision makers are provided.
Evidence against a crucial role of renal medullary perfusion in blood pressure control of hypertensive rats
Authors: Bądzyńska Bożena , Baranowska Iwona , Gawryś Olga , Sadowski Janusz
Published: October 2018

Key points

The development of new effective methods of treating arterial hypertension is hindered by uncertainty regarding its causes.

According to one widespread concept hypertension is caused by abnormal blood circulation in the kidney, specifically by reduction of blood flow through the kidney medulla; however, this causal relationship has never been rigorously verified.

We investigated whether in rats with three different forms of experimental hypertension prolonged selective elevation of renal medullary blood flow using local infusion of the vasodilator bradykinin would lower arterial pressure.

We found that increasing medullary blood flow by almost 50% did not result in alleviation of hypertension, which argues against a causal role of such changes in the control of arterial pressure and suggests that attempts at improving renal medullary circulation are not likely to be a promising approach to combating hypertension.

The crucial role of renal medullary blood flow (MBF) in the control of arterial pressure (MAP) has been widely accepted but not rigorously verified. We examined the effects of experimental selective MBF elevation on MAP, medullary tissue hypertonicity and renal excretion in hypertensive rats. We used three hypertensive rat models: (1) rats with hypertension induced by chronic angiotensin II infusions (AngII model), (2) rats with hypertension induced by unilateral nephrectomy followed by high salt diet (HS/UNX), and (3) spontaneously hypertensive rats (SHR). In acute experiments, MBF (laser‐Doppler measurement) was selectively increased with an intramedullary infusion of bradykinin (Bk) at 0.27 mg h−1 kg−1 BW over 4 h. MAP, renal artery blood flow (Transonic probe) and renal excretion parameters were measured simultaneously. In chronic studies with AngII and HS/UNX rats, Bk was infused over 2 weeks and MAP (telemetry probe) and renal excretion were repeatedly determined. In acute studies, with AngII, SHR and HS/UNX groups, Bk infusion caused a 47% increase in MBF (P < 0.01–0.001), whereas solvent infusion was without effect. During the experiments MAP decreased slightly and to the same extent with Bk and solvent infusion. Medullary tissue osmolality and [Na+] were lower in Bk‐ than in solvent‐infused AngII rats and in SHR. Two weeks of intramedullary Bk infusion tested in AngII and HS/UNX rats did not alter MAP or renal excretion; though in the latter group a significant MBF increase and medullary hypertonicity decrease was observed. Since no decrease in MAP in hypertensive rats was seen with Bk‐induced major renal medullary hyperperfusion or with a wash‐out of medullary solutes, our data argue against a crucial role of MBF in the pathogenesis of arterial hypertension.
A Data-Driven Personalized Model of Glucose Dynamics Taking Account of the Effects of Physical Activity for Type 1 Diabetes: An In Silico Study
Authors: Xie Jinyu , Wang Qian
Published: October 2018

This paper aims to develop a data-driven model for glucose dynamics taking into account the effects of physical activity (PA) through a numerical study. It intends to investigate PA's immediate effect on insulin-independent glucose variation and PA's prolonged effect on insulin sensitivity. We proposed a nonlinear model with PA (NLPA), consisting of a linear regression of PA and a bilinear regression of insulin and PA. The model was identified and evaluated using data generated from a physiological PA-glucose model by Dalla Man et al. integrated with the uva/padova Simulator. Three metrics were computed to compare blood glucose (BG) predictions by NLPA, a linear model with PA (LPA), and a linear model with no PA (LOPA). For PA's immediate effect on glucose, NLPA and LPA showed 45–160% higher mean goodness of fit (FIT) than LOPA under 30 min-ahead glucose prediction (P < 0.05). For the prolonged PA effect on glucose, NLPA showed 87% higher FIT than LPA (P < 0.05) for simulations using no previous measurements. NLPA had 25–37% and 31–54% higher sensitivity in predicting postexercise hypoglycemia than LPA and LOPA, respectively. This study demonstrated the following qualitative trends: (1) for moderate-intensity exercise, accuracy of BG prediction was improved by explicitly accounting for PA's effect; and (2) accounting for PA's prolonged effect on insulin sensitivity can increase the chance of early prediction of postexercise hypoglycemia. Such observations will need to be further evaluated through human subjects in the future.
Numerical Simulation of the Heat Transfer in the Cryoprobe of an Innovative Apparatus for Cryosurgery
Authors: Bosio Barbara , Bove Dario , Guidetti Lorenzo , Avalle Leopoldo , Arato Elisabetta
Published: October 2018

Cryosurgery is a rapidly developing discipline, alternative to conventional surgical techniques, used to destroy cancer cells by the action of low temperatures. Currently, the refrigeration is obtained via the adiabatic expansion of gases in probes used for surgeries, with the need of inherently dangerous pressurized vessels. The proposed innovative prototypal apparatus aims to reach the cryosurgical temperatures exploiting a closed-loop refrigeration system, avoiding the hazardous presence of pressurized vessels in the operating room. This study preliminarily examines the technical feasibility of the cryoablation with this machine focusing the attention on the cryoprobe design. Cryoprobe geometry and materials are assessed and the related heat transfer taking place during the cryoablation process is simulated with the aid of the computational fluid dynamics software ANSYS®Fluent. Parametric analyses are carried out varying the length of the collecting tubes and the inlet velocity of the cold carrier fluid in the cryoprobe. The values obtained for physical quantities such as the temperature reached in the treated tissue, the width of the obtained cold front, and the maximum pressure required for the cold carrier fluid are calculated and discussed in order to prove the effectiveness of the experimental apparatus and develop the machine further.
Kepler's equation and some of its pearls
Authors: Orlando Francisco G. M. , Farina C. , Zarro Carlos A. D. , Terra P.
Published: October 2018

Kepler's equation, rarely discussed in undergraduate textbooks, was enunciated by Johannes Kepler in his Astonomia Nova, published in 1609, much before the advent of the integral and differential calculus. The search for its solutions challenged the minds of brilliant researchers like Newton, Lagrange, Cauchy, and Bessel, among others. In this work, we start with a standard derivation of Kepler's equation and emphasize how it gave rise to new mathematics, like approximation methods, Bessel functions, and complex analysis. Then we apply it in two non-trivial examples. In the first one, we compute the distance reached by a projectile launched from a point at the equator of the rotating Earth. This result could be used to prove the rotation of the Earth without the need of a Foucault pendulum. In the second example, we show how two astronauts moving around the Earth along the same circular orbit could exchange a sandwich. These two apparently innocent problems are quite involved because their solutions demand the calculations of the time of flight.
Adult imitating child speech: A case study using 3D ultrasound
Authors: Feehan Colette
Published: October 2018

Voice actors are interesting for linguistic study because of their unique abilities to manipulate their vocal tract and convey different social identities. This is essentially a field of professional folk linguistics where professionals manipulate their vocal tracts to convey socially indexed, linguistic features. This study uses Ultrasound paired with acoustic analyses to address what one amateur voice actor does while imitating a child voice. Previous studies have looked at anatomical and acoustic variations defining different character types such as laryngeal setting (Teshigawara, 2003; Teshigawara & Murano, 2004) and breathy voice in Anime (Starr, 2015). This study addresses specific tongue morphology resulting from an adult imitating a child’s voice and serves as a pilot for future study of professional actors. The participant is one adult, amateur actor who produced CV syllables at different places of articulation with different vowel qualities. Notable manipulations are hyoid bone raising, gesture fronting, and tongue “troughing” where the sides of the tongue are used to narrow the oral cavity. The actor constricts the filter in multiple ways to shrink the usable space in the oral cavity and imitate the acoustic signal from a child’s vocal tract. This presentation explores the anatomical manipulations the actor utilizes.
Deconvolved conventional beamforming applied to the SWellEx96 data
Authors: Yang Tsih C.
Published: October 2018

Horizontal arrays are often used to detect/separate a weak signal and estimate its direction of arrival among many loud interfering sources and ambient noise. Conventional beamforming (CBF) is robust but suffers from fat beams and high level sidelobes. High resolution beamforming such as minimum-variance distortionless-response (MVDR) yields narrow beam widths and low sidelobe levels but is sensitive to signal mismatch and requires many snapshots of data to estimate the signal covariance matrix, which can be a problem for a moving source. Deconvolution algorithm used in image de-blurring was applied to the conventional beam power of a uniform line array (spaced at half-wavelength) to avoid the instability problems of common deconvolution methods and demonstrated with real data (T. C. Yang, IEEE J. Oceanic Eng., 43, 160–172, 2018). The deconvolved beam output yields narrow beams, and low sidelobe levels similar to MVDR and at the same time retains the robustness of CBF. It yields a higher output signal-to-noise ratio than MVDR for isotropic noise. The method is applied here to the horizontal array data collected during the SWellEx96 experiment. Bearing time record are created to compare the performance of various beamforming methods and used to track the source position.
Experimental performance evaluation of underwater active detection and positioning system
Authors: Ma Lin , Zhao Anbang , Gulliver T. Aaron , Zeng Caigao
Published: October 2018

Underwater targets active detection and positioning are of increasing challenges in various underwater practical engineering applications. The performance of the proposed detection and positioning algorithms are validated and evaluated by designed open-lake experiments. The widely used matched-filter, conducted in frequency-domain, is improved by normalized least mean square algorithm to achieve the better detection ability. The improved detector is applied to the underwater targets detection in these experiments. Post-processing technique based on autocorrelation is proposed to enhance the performance of detection by cancelling the noise existing in frequency-domain. The underwater target is located on the basis of the time-delay and azimuth estimation. The open-lake experimental results show that the detection and positioning system is robust and effective in the complex underwater environment. The designed model and these proposed techniques provide a better way to underwater target active detection and positioning.
Ultrasonic characterization of synthetic three-dimensional polycrystals
Authors: Norouzian Musa , Matz Nathanial , Islam Showmic , Turner Joseph A.
Published: October 2018

Ultrasonic nondestructive testing has been increasingly used to characterize heterogeneities of polycrystalline materials. With such techniques, the interactions of coherent ultrasonic waves with grain boundaries result in scattering. Such scattered waves carry information regarding the physical properties of the scatterer. Therefore, microstructural information can be obtained by quantifying the scattered response. Current diffuse ultrasonic backscatter models include several assumptions about the macroscopic and microscopic properties of the polycrystals. In this presentation, the sensitivity of grain size characterization to such assumptions is investigated using simulated microstructures. Several polycrystals with cubic crystal symmetry and randomly oriented grains are simulated using Dream.3D. This study applies the single scattering model in which the longitudinal-to-longitudinal configuration is considered for the incident and the scattered waves and limited to the weakly-scattering regime. In each configuration, the theoretical results are compared with results from the synthetic volumes. The results demonstrate distinct differences between the theory and the simulation. For example, the theoretical scattering cross section for a Voigt-averaged copper polycrystal at 15 MHz is found to be about three times larger than the value based on the Dream.3D microstructure. Finally, the influence of grain size distribution and grain elongation on the ultrasonic models are investigated.
Interfacial effects in underwater acoustic panel measurements
Authors: Szabo Jeffrey , Bent Adam
Published: October 2018

Underwater acoustic panel measurements were conducted on single layers of rubber or metal, and on rubber/metal bilayers that had been fabricated using various adhesives or attachment methods. Reflection and transmission measurements were carried out on submerged panels using a parametric array source. It was found that the condition of the various interfaces in the system (water/rubber, water/metal, or rubber/metal) had a dominant effect on the measured acoustic properties. Single layer (metal or rubber) panels with smooth surfaces behaved in accordance with theoretical predictions, but panels with even a small amount of surface roughness did not. This was attributed to a non-ideal water/sample interface, most likely due to the presence of air bubbles. The effect of various surface treatments on the acoustic behaviour of the panels was investigated. Different adhesion methods for fabricating aluminum/rubber bilayers were tested for their practicality and effects on underwater acoustic properties. Nitrile butadiene rubber and aluminum panels were adhered to one another using pressure sensitive adhesive, contact cement, banded duct tape, or epoxy, and tested in transmission and reflection. The results were strongly dependent on adhesion method, with only one method (epoxy cured under 15 psi pressure) giving results that matched theoretical predictions.
Reflection of an ultrasonic wave from the bone-implant interface: A numerical study
Authors: Hériveaux Yoann , Nguyen Vu-Hieu , Haiat Guillaume
Published: October 2018

Quantitative ultrasound are used to characterize and stimulate osseointegration processes at the bone-implant interface (BII). However, the interaction between an ultrasonic wave and the implant remains poorly understood. This study aims at investigating the sensitivity of the ultrasonic response to the microscopic and macroscopic properties of the BII and to osseointegration processes. The reflection coefficient R of the BII was modeled for different frequencies using a two-dimensional finite element model. The implant surface was modeled by a sinusoidal function with varying amplitude and spatial frequency and then by considering actual implant surface profiles. A soft tissue layer of thickness W was introduced between bone tissue and the implant in order to model non-mineralized fibrous tissue. For microscopic roughness, R is shown to increase from around 0.55 until 0.9 when k.W increases from 0 to 1 and to be constant for k.W>1. These results show that R depends on the properties of bone tissue located at a distance comprised between 1 and 25 μm from the implant surface. For macroscopic roughness, R is highly dependent on the roughness amplitude, which may be explained by phase cancellation and multiple scattering effects for high roughness parameters.
Determining a relationship between mockup size and transmitted vibration
Authors: Gartenburg Paul , Golden Matthew V.
Published: October 2018

Testing fitness flooring mockups is sometimes required to prove the efficacy of a fully installed floor. Constructing these in-situ mockups can be labour intensive and costly. Keeping mockup sizes low is beneficial from these standpoints but can be detrimental from an acoustical standpoint. The purpose of this paper is to understand the relationship between mockup size and transmitted vibration as a result of heavy weight impacts. To achieve this, mockups of varied sizes and buildups ranging from 2′ × 2′ to 10′ × 0′ were tested and resultant vibrations in the structural slab were recorded by two accelerometers adhered to the slab. This paper analyzes the recorded results for both locally reactive and resonantly reactive floors to provide insight in determining what mockup size is appropriate without significantly compromising the validity of the results.
The sound insulation performance of mass timber building elements
Authors: Mahn Jeffrey
Published: October 2018

Mass timber constructions have been gaining popularity in Canada since provincial building codes were changed to allow for taller buildings of mass timber elements. Common mass timber elements include cross-laminated timber, nail-laminated timber, dowel-laminated timber, and glued laminated timber. Many of these elements have been in use for decades, but much still needs to be learned in terms of the transmission of structure-borne noise between elements and the transmission loss and radiation efficiency of the elements with and without linings. Recent and ongoing studies on cross-laminated and nail-laminated elements conducted at the National Research Council have investigated many of the unknowns and a summary of the results are presented in this paper.
High frequency propagation in a waveguide with an expanding section
Authors: Ginsberg Jerry H. , Feit David
Published: October 2018

A waveguide whose walls have a constant local impedance is readily analyzed if its cross section is uniform with a standard shape. This is not true if the cross section expands or contracts. The (one-dimensional) Webster horn equation typically is used for low frequency propagation in such configurations, but doing so restricts consideration to situations where the size of the cross section changes slowly over the scale of a wavelength. Somewhat paradoxically, a waveguide consisting of a sequence of different sized uniform segments has been the subject of numerous analyses that are not limited to low frequencies. The present work extends one such analysis, which uses a collocation technique at discontinuous junctions, to a two-dimensional configuration in which a transition section expands linearly. The field in each section is described as a modal series, whose terms are the product of a transverse standing mode and two phasors for axial propagation. Cartesian coordinates are used to describe the field within the uniform sections, whereas a polar coordinate description of the field in the expansion section facilitates satisfying rigid wall conditions. Various schemes for arranging the collocation points are discussed, and convergence of the series is examined.
Optimizing acoustic diffusion of an architectural feature using finite-difference time-domain
Authors: Brill Laura C. , Strong John T.
Published: October 2018

Parametric design is gaining in popularity as a design tool; however, rigorous analysis of the acoustic characteristics of parametrically designed surfaces typically requires testing physical mockups of a small sample of candidate designs. A computational method using a combination of finite-difference time-domain (FDTD) analysis and a genetic optimization algorithm has been developed to analyze a large number of candidate designs and select the best performers. In this case study, an architect’s aesthetic vision was translated into geometric parameters used by a genetic algorithm to optimize acoustic diffusion performance. FDTD was used to simulate an impulse response and analyze the frequency response of reflective/diffusive geometry with a resolution of up to 11 kHz. The process utilized GPU computing clusters available through Amazon Web Services (AWS) to accelerate the analysis. The current availability and relative cost-effectiveness of cloud computing resources makes wave-based acoustic analysis a more viable and efficient option. The methods and resources discussed in this paper allow acoustic performance to be integrated into the architectural optimization process thereby making acoustic performance an active consideration in an iterative design approach.
Optimizing calculation points using Gaussian process regression
Authors: Kamrath Matthew , Jean Philippe , Maillard Julien , Picaut Judicaël
Published: October 2018

Many applications in computational acoustics calculate a value (e.g., sound pressure level) at many different locations to approximate the value throughout a region using interpolation. Often, the points are uniformly or exponentially spaced without a rigorous procedure to optimize the locations because directly minimizing the interpolation error is too computationally expensive. Instead, the interpolation error can be indirectly reduced by minimizing the maximum variance estimated using Gaussian process regression. This approach is less expensive because the variance at a point is not a function of the value at that point. Thus, each evaluation of the objective function (i.e., the maximum variance) does not require additional acoustical computations, which mitigates the cost of the objective function. As an example, this procedure is applied to an outdoor sound propagation case to approximate the insertion loss of a 3 m tall T-shaped barrier compared to 3 m tall straight barrier, which are modeled using the boundary element method. In this case, the optimized locations have a smaller interpolation error than uniformly and exponentially distributed points.
Optimizing speech recognition in realistic environments for children who wear hearing aids
Authors: McCreery Ryan W. , Walker Elizabeth , Brennan Marc
Published: October 2018

Children with hearing loss are immersed in listening situations with poor signal-to-noise ratios and high levels of reverberation. Children’s ability to effectively communicate in acoustically challenging listening situations has an impact on language development and academic and social functioning. Children with hearing loss who use hearing aids perform more poorly than peers with normal hearing when listening in noise and reverberation. However, speech understanding among children with hearing loss is heterogeneous and most previous research has focused primarily on the effect of a child’s degree of hearing loss derived from the audiogram. Our research explores additional factors that contribute to individual differences in speech recognition in adverse acoustic conditions for children with hearing loss. This work has focused on three factors that explain individual differences in speech recognition in noise among children who use hearing aids: 1) the degree to which speech audibility is restored by the hearing aid(s), 2) the child’s language abilities, and 3) the child’s cognitive abilities, including working memory and selective attention. The relationships between speech recognition and these factors, as well as the clinical implications of these findings, will be described.
Spectral modulation detection in adolescents with normal hearing or cochlear implants predicts some language skills, but not others
Authors: Nittrouer Susan , Lowenstein Joanna H. , Sinex Donal
Published: October 2018

Previous outcomes of an ongoing longitudinal study involving children with cochlear implants (CIs) have revealed that these children demonstrate especially large deficits in two areas: (1) language skills dependent upon phonological structure; and (2) speech-in-noise recognition. Morphosyntactic skills appear closer to typical. We have hypothesized that both the phonological deficit and the speech-in-noise problems arise from poor spectral resolution. To test this hypothesis we measured children’s spectral modulation detection (SMD). Participants were14-year-old children with normal hearing (49) or with CIs (42). A 3-interval, forced-choice procedure was used in which two stimuli were unmodulated noises and one was a noise modulated at a rate of 0.5 ripples per octave (rpo). The 70.7% threshold for SMD was estimated adaptively. Other measures included tests of phonological awareness and processing, vocabulary and syntactic abilities, and speech recognition in single- or multi-talker babble, as well as in speech-shaped noise. Children with CIs had slightly higher SMD thresholds, and poorer performance on all other measures. For both groups, SMD thresholds were related to phonological skills and speech-in-noise recognition, but not to vocabulary or syntactic abilities. Outcomes were interpreted as suggesting that phonological sensitivity and speech-in-noise recognition depend upon spectral resolution, but morphosyntactic skills do not.
Remote focusing of elastic waves in complex structures using time reversal of acoustic waves
Authors: Farin Maxime , Prada Claire , de Rosny Julien
Published: October 2018

Remotely assessing the state of damage of thin plates or beams within a complex structure is a burning issue in many industrial problems. A time-reversal technique is used to focus a short and localized elastic impulsion on a thin plate using a network of loudspeakers. The generated plate vibration is measured using a laser vibrometer. We built an experimental setup to mimic a complex structure, with several thin plates attached close to each others inside a cylinder. We show that the acoustic method allows us to put a targeted plate in vibration inside the cylinder, without exciting the other plates in the same structure. The time-reversal technique takes advantage of the strong wave reverberation caused by the presence of the complex structure around the plate, which creates virtual sound sources, and improves the focusing on the plate compared to that obtained when the plate has nothing around it. The ratio of plate vibration energy over emitted acoustic energy is about 1%. Finally, we create a small defect on a plate and assess whether the defaults can be detected from changes in the plate vibration modes. Our experimental results are compared with finite elements simulations.