bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Spinal Cord Stimulation and Neuropathic Pain: Mechanism of Action, Technical Aspects, and Effectiveness
Authors: Smits Helwin , van Kleef Maarten , Holsheimer Jan , Joosten Elbert A. J.
Published: July 2012

Abstract:  Spinal cord stimulation (SCS) is a valuable treatment for chronic intractable neuropathic pain. Although SCS has gone through a technological revolution over the last four decades, the neurophysiologic and biochemical mechanisms of action have only been partly elucidated. Animal experimental work has provided some evidence for spinal as well as supraspinal mechanisms of neuropathic pain relief of SCS. A SCS computer model of the electrical properties of the human spinal cord revealed many basic neurophysiologic principles that were clinically validated later on. The main question in clinical SCS is how to further improve the effectiveness of SCS as there is still a significant failure rate of 30%. In this context, experimental studies are needed to elucidate which target pain neuron(s) are involved, as well as with what exact electrical stimulation this target neuron can be influenced to produce an optimal supapression of neuropathic pain. This article reviews the basic clinical and experimental technical aspects in relation to the effectiveness of SCS in view of recent understanding of the dorsal horn pain circuit involved. These data may then result in experiments needed for an improved understanding of the mechanisms underlying SCS and consequently lead to improvement and increased effectiveness of SCS in neuropathic pain as a clinical therapy.
Spatial and Scale‐Dependent Controls on North American Pan‐Arctic Minimum River Discharge
Authors: Rennermalm Asa K. , Bring Arvid , Mote Thomas L.
Published: July 2012

Spatial patterns of minimum monthly river discharge in the North American Pan‐Arctic and its potential controls are explored with geographically weighted regression (GWR). Minimum discharge is indicative of soil water conditions; therefore, understanding spatial variability of its controls may provide insights into patterns of hydrologic change. Here, GWR models are applied to determine a suitable combination of independent variables selected from a set of eight variables. A model specification with annual mean river discharge, temperature at time of minimum discharge, and biome describes well the spatial patterns in minimum discharge. However, minimum discharge in larger watersheds is influenced more by temperature and biome distributions than it is in small basins, suggesting that scale is critical for understanding minimum river discharge. This study is the first to apply GWR to explore spatial variation in Pan‐Arctic hydrology.

Factores de control espaciales y dependientes de escala en las descargas fluviales mínimas de ríos Pan‐Articos en Norteamérica.

El artículo explora los patrones espaciales de caudales fluviales mínimos mensuales la región pan‐ártica de Norteamérica y sus posibles factores de control haciendo uso de una regresión ponderada geográficamente (geographically weigted regression‐GWR). Los caudales mínimos son indicadores de las condiciones del agua en el suelo, y por lo tanto el entendimiento de la variabilidad espacial de los factores que los controlan puede ayudar a comprender los patrones de cambio hidrológico. En el presente estudio, varios modelos de tipo GWR son aplicados para determinar una combinación adecuada de variables independientes seleccionadas a partir de un conjunto de ocho variables. El modelo que utiliza la media anual media de descarga fluvial, la temperatura en el momento de caudal mínimo, y el bioma, proporciona una buena descripción de los patrones espaciales en la descarga mínima. Sin embargo, en las cuencas hidrográficas grandes, la descarga mínima está más influenciada por la temperatura y la distribución de los biomas que en el caso de cuencas más pequeñas, lo que sugiere que la escala es fundamental para entender la descarga mínima fluvial. Este estudio es el primero en aplicar GWR para comprender la variación espacial en la hidrología de la región pan‐ártica.

基于GWR（地理加权回归模型）对北美泛北极地区月份最小河流流量的空间模式和潜在控制进行研究。最小流量暗示水土条件；因此，理解空间分异及控制可深刻理解水文变化的模式。GWR可从8个变量中提取一组独立变量的适当组合。通过年均河流流量、最小流量时的温度和生物群落，来描述最小下泄流量的空间格局。在大范围流域中，最小流量受到温度和生物群落分布的影响大于在小规模的流域，揭示出在河流最小流量分析中尺度是非常重要的。本文首次将GWR应用于泛北极水文空间异质性分析。
The influence of glutamatergic antagonism on motor variability, and comparison to findings in schizophrenia patients
Authors: Johnsen Erik , Fasmer Ole Bernt , van Wageningen Heidi , Hugdahl Kenneth , Hauge Erik , Jørgensen Hugo A.
Published: July 2012

Objective

The primary aim of this explorative study was to investigate the influence of the glutamatergic N‐methyl‐d‐aspartate (NMDA) receptor antagonist memantine on motor activity in healthy subjects. Secondarily, we wanted to compare these data to findings in a sample of schizophrenia patients.

Methods

The healthy subjects acted as their own controls in an open‐within‐subject design. Motor activity was recorded with an actigraph worn for 24 h in the drug‐free, and steady‐state memantine conditions, respectively. Motor activity levels for 1‐min intervals were analysed by means of both linear and nonlinear methods. The schizophrenia patients were monitored only once, without memantine manipulation.

Results

The root mean square successive differences (RMSSD) and the RMSSD/SD ratio were increased by memantine, and memantine was also associated with lower autocorrelation (lag 1) but in recordings from the right arm only. These movement patterns partly corresponded to those found in a sample of drug‐treated schizophrenia patients. Total activity level, standard deviation (SD) and sample entropy were not significantly different in the memantine versus drug‐free condition.

Conclusion

The findings suggest a role for the NMDA receptor in the regulation of motor activity in healthy individuals as memantine increased the variability in the motor recordings and the alterations between adjacent motor recordings. It is suggested that the findings may be relevant to the role played by glutamate and the NMDA receptor functioning to the motor disturbances in schizophrenia.
Folic acid fortification prevents neural tube defects and may also reduce cancer risks
Authors: Jägerstad Margaretha
Published: July 2012

The prevalence of neural tube defect (NTD)‐affected pregnancies ranges between 0.4 and 2/1000 pregnancies in EU. NTDs result in severe malformations and sometimes miscarriages. Children born with NTD suffer for the rest of their life of disability and chronic healthcare issues, and many women therefore choose termination of pregnancy if NTD is diagnosed prenatally. Women planning for pregnancy are recommended to eat 400 μg folic acid/d, whereas average figures across Europe indicate intakes of ∼250 μg/d for women of fertile age, a gap that could be bridged by implementation of folic acid fortification. The results of mandatory folic acid fortifications introduced in USA and Canada are a decrease between 25 and 45% of NTD pregnancies.

Conclusion:  Evidence‐based NTD prophylaxis is now practised in more than 60 countries worldwide. EU countries worry over possible cancer risks, but ignore a wealth of studies reporting decreasing cancer risks with folate intakes at recommended levels. Currently, there are indications of a U‐shaped relationship, that is, higher cancer risks at low folate intakes (<150 μg/day) and highly elevated folate intakes (>1 mg/day), respectively. However neither the global World Cancer Research review nor EU’s European Food Safety Authority report present data on increased cancer risk at physiological folate intake levels. Therefore, EU should act to implement folic acid fortification as NTD prophylaxis as soon as possible.
Simple and effective approach for the treatment of traumatic wounds in non‐diabetic patients: a prospective open study
Authors: Nagoba Basavraj , Gandhi Rajan , Wadher Bharat , Rao Arunkumar , Selkar Sohan
Published: July 2012

Infection is one of the most important obstacles in the wound‐healing process. Conventional methods used for the treatment of wound infections have their own limitations and hence, are difficult to control. If infection is not addressed well in time, it will further increase morbidity and cost of treatment. An attempt was made to develop a simple and effective treatment modality by using citric acid as the sole antimicrobial agent to control bacterial infections of traumatic wounds. A total of 259 cases of traumatic wounds infected with a variety of bacteria were investigated for culture and susceptibility, and susceptibility to citric acid. Citric acid ointment (3%) was applied to traumatic wounds to determine its efficacy in their treatment of traumatic wounds. In a culture and susceptibility study, a total of 369 aerobic bacteria and 7 fungi were isolated, with Staphylococcus aureus (30·31%) being the most common isolate and ciprofloxacin (61·43%) being the most effective agent. All the isolates were found to be inhibited by citric acid in in vitro studies (minimum inhibitory concentration – 500–2500 µg/ml). Citric acid ointment was found effective in controlling infections. Out of 259 cases, 244 (around 95%) were healed completely in 5–25 applications of 3% citric acid. As citric acid has antibacterial activity and wound‐healing property; hence it is the best alternative for the treatment of traumatic wounds. Besides these properties, citric acid has no adverse effects and it is a good dressing agent.
Progressive aortic dilation after aortic valve replacement
Authors: Yuan Shi‐Min , Lavee Jacob
Published: July 2012

Aim

Ascending aortic dilation is not an uncommon complication following aortic valve replacement (AVR). However, the clinical features of ascending aortic dilation after AVR are rarely described. The etiologies responsible for the development of progressive aortic dilation in such patients are not fully understood.

Patients and Methods

From January 2006 to November 2008, 10 consecutive patients requiring ascending aortic replacement after initial AVR were enrolled into this study cohort.

Results

The etiologies of the aortic valves subjected to the initial AVR were congenitally bicuspid (aortic valve regurgitant) in two (20 per cent), rheumatic aortic stenosis in three (30 per cent) and rheumatic combined stenotic and regurgitant aortic valve in five (50 per cent) patients, respectively. The surgical indications for subsequent aorta replacement were ascending aortic dilation in eight (80 per cent), aortic dissection in one (10 per cent), and aortic dilation and dissection in one (10 per cent) patient, respectively. The interval between initial AVR and aorta replacement was 8–32 (mean: 17.1 ± 9.1) years. The dimensions of the aortic root and ascending aorta late after AVR were 4.64 ± 1.20 cm and 5.06 ± 0.69 cm, respectively. There were no significant differences in the extent of expansion of the aortic root and the ascending aorta (0.8810 ± 0.7475 cm vs 1.0800 ± 0.6202 cm, P = 0.5252). The mean expansion rates of the aortic root and the ascending aorta were 0.052 cm/year and 0.063 cm/year between initial AVR and subsequent aorta replacement, respectively. The dimensions of the aortic root and ascending aorta measured at the initial operations and the aorta replacement did not seem to have any differences between patients with a native bicuspid aortic valve and those with a tricuspid aortic valve. No significant correlation was found between the dimension of the aortic root or ascending aorta and the independent variables.

Conclusion

Aortic dilation might develop in younger patients late after AVR with time. Aortic dilation might involve the aortic root and ascending aorta. Neither a significant difference nor a consistent correlation was noted between expansion dimensions of aortic root and ascending aorta dilation. In patients, AVR cannot effectively hold back aortic dilation, and the mean expansion rates of the aortic root and of the ascending aorta are above 0.05‐0.06 cm/year after AVR. Early surgical intervention is necessary in order to prevent aortic rupture or dissection, and long‐term follow up is warranted in such patients.
One‐year review of the incidence of brain tumours in Hong Kong Chinese patients as part of the Hong Kong Brain and Spinal Tumours Registry
Authors: Pu Jenny K.S. , Ng Gloria K.B. , Leung Gilberto K.K. , Wong Chi‐Keung
Published: July 2012

Aim

There is a lack of recent data regarding the incidence of central nervous system (CNS) tumours in Hong Kong patients of Chinese origin. The aim of this study was to provide a current registry of brain and CNS tumour incidence in Hong Kong, which would contribute to the current knowledge of brain tumour epidemiology.

Patients and Methods

Prospective data were collected from neurosurgical centres in Hong Kong between July 2008 and June 2009. Demographic and diagnostic data were collected for each patient diagnosed with a brain tumour, and collated at a central coordination centre. Diagnosis was confirmed either histologically or radiologically.

Results

There were 1031 newly‐diagnosed cases of spinal/intracranial tumours, 759 of which were primary tumours. The estimated annual incidence of spinal/intracranial tumours was 14.7 per 100 000. The annual incidence of primary CNS tumours was 10.8 per 100 000, and 3.5 per 100 000 for meningiomas. A total of 70 high‐grade gliomas (incidence rate of 1/100 000) and 171 pituitary tumours were diagnosed, both of which were more prevalent in the 45–64‐year age group. Meningiomas and pituitary tumours were more common in females. In paediatric patients, there were 36 cases of newly‐diagnosed brain tumours, glioma being the most common.

Conclusion

The annual incidence rate of malignant gliomas was one per 100 000 in the Hong Kong population of Chinese origin. From comparisons with other studies, this suggests geographical and racial differences in the incidence of brain tumours, and warrants further collaboration and research regarding brain tumour epidemiology.
Low‐level laser therapy reduces time to ambulation in dogs after hemilaminectomy: a preliminary study
Authors: Draper W.E. , Schubert T.A. , Clemmons R.M. , Miles S.A.
Published: July 2012

Objectives

A prospective study to determine if low‐level laser therapy and surgery for intervertebral disk herniation encourage ambulation faster than surgery alone.

Methods

Thirty‐six dogs with acute paraparesis/paraplegia due to acute intervertebral disk herniation were evaluated and given a modified Frankel score. Dogs with scores 0 to 3 were included in the study. Dogs were assigned to the control group (1) or the laser treatment group (2) based on alternating order of presentation. All dogs underwent surgery for their herniated disk. Dogs in group 2 were treated postoperatively with low‐level laser therapy daily for five days, or until they achieved a modified Frankel score of 4. A 5×200‐mW 810‐nm cluster array was used to deliver 25 W/cm2 to the skin. All dogs were scored daily by the investigators using the modified Frankel scoring system.

Results

The time to achieve a modified Frankel score of 4 was significantly lower (P=0·0016) in the low‐level laser therapy group (median 3·5 days) than the control group (median 14 days).

Clinical Significance

Low‐level laser therapy in combination with surgery decreases the time to ambulation in dogs with T3‐L3 myelopathy secondary to intervertebral disk herniation.
B cells set trends: Lessons from multiple sclerosis
Authors: Lawrie Sarah , Bar‐Or Amit
Published: July 2012

Until relatively recently, B cells were viewed as relatively passive recipients of T cell help, serving the primary normal function of protective antibody production. Similarly, their role in immune‐mediated diseases, including multiple sclerosis (MS), was traditionally ascribed to production of pathogenic autoantibodies. However, new insights gained from both animal models and in humans, including studies of selective B cell targeting in patients, have shed light on non‐antibody‐mediated functions of B cells as immune regulators in both health and disease. Here, we consider the significance of the recent success of B cell depletion in patients with MS. We submit that it is no longer a question of whether
B cells contribute to MS, but how
B cells do so. In this review, we consider concepts of the different antibody‐dependent and ‐independent biological roles that B cells might play in MS pathophysiology. Important data from the commonly used animal model of MS, experimental autoimmune encephalomyelitis (EAE), continues to contribute to our understanding of the molecular cascades involved in peripheral immune regulation and in immune‐neural interactions that might be relevant to inflammatory events of multiple sclerosis. We focus this review on results from human‐based studies, occasionally drawing on observations from animal models to highlight specific principles.
Incidence and mortality of breast cancer in China, 2008
Authors: Chen Wan‐qing , Zheng Rong‐shou , Zeng Hong‐mei , Zhang Si‐wei , Li Guang‐lin , Wu Liang‐you , He Jie
Published: July 2012

Background

Female breast cancer incidence and mortality data for the duration of 2008, in China, retrieved from the National Central Cancer Registry, was analyzed.

Methods

In 2008, there were 56 registries that submitted cancer registration data. Based on the criteria of data quality, a total of 41 registries' data met the requirement and were accepted for analysis. The incidence and mortality rates of breast cancer in females were calculated, including age specific rates, age‐standardized rates, proportions, and cumulative rates, stratified by areas (urban/rural).

Results

The number of cases included from 41 registries was 66 138 784, with 32 798 187 of these cases found in women (25 898 251 in urban areas and 6 899 936 in rural areas). There were 15 625 new cases reported and 3414 deaths of women with breast cancer, resulting in a mortality to incidence ratio of 0.22. The morphological verified rate was 91.96%, and 0.43% of cases were identified by death certificate only. The crude cancer incidence rate in all areas was 47.64/100 000, and the Age‐Standardized Incidence Rates by Chinese standard population, (ASIRC) and World standard population (ASIRW) were 25.26/100 000 and 31.71/100 000, respectively. The cumulative incidence rate (0–74 years old) was 3.44%. Both crude and adjusted incidence rates in urban areas were much higher than those in rural areas. The crude cancer mortality was 10.41/100 000, and the Age‐Standardized Mortality Rates by Chinese standard population (ASMRC) and by World population (ASMRW) were 4.90/100 000 and 6.48/100 000, respectively. The cumulative mortality rate (0–74 years old) was 0.071%. Age‐adjusted mortality rates in urban areas were also higher than in rural areas. Age specific incidence rates peaked in age group 50–54 in all areas (108.27/100 000) and in urban areas (119.68/100 000). It reached the peak in the 55–59 age group for rural women. Age specific mortalities rose with the increase of age for both women in urban and rural areas, with mortality rates of 76.16/100 000 and 23.73/100 000 in age groups of 85 and above, respectively.

Conclusions

Breast cancer is the most common cancer diagnosed in Chinese women. Preventative measures, such as health education and screening, are needed in the general population, but especially for those in the high‐risk group found in urban areas.
FOREST BIOENERGY ADOPTION FOR A RISK‐AVERSE LANDOWNER UNDER UNCERTAIN EMERGING BIOMASS MARKET
Authors: HALLMANN FANFAN W. , AMACHER GREGORY S.
Published: July 2012

AbstractThis paper examines a land use problem where a risk‐averse representative landowner is uncertain about the timing and extent of a future biomass market emergence. The risk‐averse landowner is expected to maximize his or her expected utility of net present value from three land uses: agriculture, conventional forestry, and bioenergy forestry. Varying land quality, expected price jumps, and the timing of biomass market emergence are incorporated into the analysis. Under constant risk aversion, the simulation results show that the level of risk aversion has a significant influence on land allocation. The analysis also includes a discussion of how transaction costs affect land use change. The results offer insights into policy making for promoting forest bioenergy market development.
Determination of serum anti‐Müllerian hormone concentrations for the diagnosis of granulosa‐cell tumours in mares
Authors: BALL B. A. , ALMEIDA J. , CONLEY A. J.
Published: July 2012

Reasons for performing study:Endocrinological assays are important for evaluation of mares with granulosa‐cell tumours (GCTs), and our research in mares indicates that anti‐Müllerian hormone (AMH) may be a good biomarker for this type of ovarian tumour.

Objectives:To evaluate the use of serum AMH concentrations for endocrine diagnosis of GCTs in mares.

Methods:Archived serum samples (n = 403) previously assayed for determination of serum inhibin, testosterone and progesterone concentrations (GCT panel) were assayed for serum AMH concentrations using a heterologous enzyme‐linked immunosorbent assay previously validated by our laboratory. For a subset (n = 44) of these samples, a clinical diagnosis of GCT was confirmed by histopathology.

Results:Overall, the sensitivity of AMH (98%) for detection of histologically confirmed GCTs was significantly (P<0.05) greater than that of either inhibin (80%) or testosterone (48%) or the combination of inhibin and testosterone (84%).

Conclusions:Determination of serum AMH concentrations is a useful biomarker for detection of GCTs in the mare.

Potential relevance:Measurement of serum AMH concentrations can be used for diagnosis of GCTs in the mare. As serum AMH concentrations do not vary significantly during the oestrous cycle or pregnancy, interpretation of these results is not confounded by these physiological states.
Antimicrobial‐associated diarrhoea in three equine referral practices
Authors: BARR B. S. , WALDRIDGE B. M. , MORRESEY P. R. , REED S. M. , CLARK C. , BELGRAVE R. , DONECKER J. M. , WEIGEL D. J.
Published: July 2012

Reasons for performing study:Although antimicrobial‐associated diarrhoea (AAD) is the most frequently observed adverse effect of antimicrobial therapy in horses, few multicentred studies on the prevalence of AAD have been performed.

Objectives:To determine the prevalence of AAD in horses that developed diarrhoea after antimicrobial treatment for nondiarrhoeic conditions and identify the antimicrobials used.

Methods:The 2009 database of 3 referral hospitals was searched to identify nonhospitalised horses (weanling age or older) treated with antimicrobials for nongastrointestinal conditions. Horses with these criteria that presented with diarrhoea during 2009 were included in the study. Additional information, including antimicrobial administered and results of faecal pathogen testing, was gathered on each hospitalised case.

Results:Of the 5251 horses treated with antimicrobials for nongastrointestinal signs, 32 were diagnosed with probable AAD, a prevalence of 0.6% (95% confidence interval: 0.43–0.86%). The AAD‐diagnosed horses had an 18.8% (6/32) mortality rate. Horses with AAD had been treated for an average of 4.2 days. The most frequently used antimicrobials in horses with AAD were gentamicin in combination with penicillin (n = 7), enrofloxacin (n = 7) and doxycycline (n = 4).Clostridium difficilewas identified in faecal samples from 4 horses, 2 of which died andSalmonellafrom 3 horses.

Conclusions:Results indicated that the prevalence of AAD is low. Any antimicrobial class commonly used in equine practice is a potential cause of equine AAD. Other risk factors, such as opportunistic enteropathogens, may play a part in the development of diarrhoea secondary to antimicrobial usage.

Potential relevance:Although the risk of equine AAD is low, this sequela of antimicrobial treatment is possible especially when opportunistic enteropathogens or other risk factors are present. Because drugs from any antimicrobial class can be potentially involved in AAD, clinicians have additional incentive to ensure the judicious use of antimicrobial agents.
Roles of the non-medical prescribing leads within organisations across a Strategic Health Authority: perceived functions and factors supporting the role
Authors: Lim Rosemary Hwee Mei , Courtenay Molly , Fleming Gail
Published: July 2012

Objectives

Extending the roles of nurses, pharmacists and allied health professionals to include prescribing has been identified as one way of improving service provision. In the UK, over 50 000 non-medical healthcare professionals are now qualified to prescribe. Implementation of non-medical prescribing ( NMP) is crucial to realise the potential return on investment. The UK Department of Health recommends a NMP lead to be responsible for the implementation of NMP within organisations. The aim of this study was to explore the role of NMP leads in organisations across one Strategic Health Authority (SHA) and to inform future planning with regards to the criteria for those adopting this role, the scope of the role and factors enabling the successful execution of the role.

Methods

Thirty-nine NMP leads across one SHA were approached. Semi-structured telephone interviews were conducted. Issues explored included the perceived role of the NMP lead, safety and clinical governance procedures and facilitators to the role. Transcribed audiotapes were coded and analysed using thematic analytical techniques.

Key findings

In total, 27/39 (69.2%) NMP leads were interviewed. The findings highlight the key role that the NMP lead plays with regards to the support and development of NMP within National Health Service trusts. Processes used to appoint NMP leads lacked clarity and varied between trusts. Only two NMP leads had designated or protected time for their role. Strategic influence, operational management and clinical governance were identified as key functions. Factors that supported the role included organisational support, level of influence and dedicated time.

Conclusion

The NMP lead plays a significant role in the development and implementation of NMP. Clear national guidance is needed with regards to the functions of this role, the necessary attributes for individuals recruited into this post and the time that should be designated to it. This is important as prescribing is extended to include other groups of non-medical healthcare professionals.
Model for bubble pulsation in liquid between parallel viscoelastic layers
Authors: Hay Todd A. , Ilinskii Yurii A. , Zabolotskaya Evgenia A. , Hamilton Mark F.
Published: July 2012

A model is presented for a pulsating spherical bubble positioned at a fixed location in a viscous, compressible liquid between parallel viscoelastic layers of finite thickness. The Green’s function for particle displacement is found and utilized to derive an expression for the radiation load imposed on the bubble by the layers. Although the radiation load is derived for linear harmonic motion it may be incorporated into an equation for the nonlinear radial dynamics of the bubble. This expression is valid if the strain magnitudes in the viscoelastic layer remain small. Dependence of bubble pulsation on the viscoelastic and geometric parameters of the layers is demonstrated through numerical simulations.
Minimization of the mean square velocity response of dynamic structures using an active-passive dynamic vibration absorber
Authors: Cheung Y. L. , Wong W. O. , Cheng L.
Published: July 2012

An optimal design of a hybrid vibration absorber (HVA) with a displacement and a velocity feedback for minimizing the velocity response of the structure based on the H2 optimization criterion is proposed. The objective of the optimal design is to reduce the total vibration energy of the vibrating structure under wideband excitation, i.e., the total area under the velocity response spectrum is minimized in this criterion. One of the inherent limitations of the traditional passive vibration absorber is that its vibration suppression is low if the mass ratio between the absorber mass and the mass of the primary structure is low. The active element of the proposed HVA helps further reduce the vibration of the controlled structure, and it can provide very good vibration absorption performance even at a low mass ratio. Both the passive and active elements are optimized together for the minimization of the mean square velocity of the primary system as well as the active force required in the HVA. The proposed HVA was tested on single degree-of-freedom (SDOF) and continuous vibrating structures and compared to the traditional passive vibration absorber.
Post-low bouncing in Mandarin Chinese: Acoustic analysis and computational modeling
Authors: Prom-on Santitham , Liu Fang , Xu Yi
Published: July 2012

Post-low bouncing is a phenomenon whereby after reaching a very low pitch in a low lexical tone, F0 bounces up and then gradually drops back in the following syllables. This paper reports the results of an acoustic analysis of the phenomenon in two Mandarin Chinese corpora and presents a simple mechanical model that can effectively simulate this bouncing effect. The acoustic analysis shows that most of the F0 dynamic features profiling the bouncing effect strongly correlate with the amount of F0 lowering in the preceding low-tone syllable, and that the additional F0 raising commences at the onset of the first post-low syllable. Using the quantitative Target Approximation model, this bouncing effect was simulated by adding an acceleration adjustment to the initial F0 state of the first post-low syllable. A highly linear relation between F0 lowering and estimated acceleration adjustment was found. This relation was then used to effectively simulate the bouncing effect in both the neutral tone and the full tones. The results of the analysis and simulation are consistent with the hypothesis that the bouncing effect is due to a temporary perturbation of the balance between antagonistic forces in the laryngeal control in producing a very low pitch.
Scattering of acoustic waves by macroscopically inhomogeneous poroelastic tubes
Authors: Groby J.-P. , Dazel O. , Depollier C. , Ogam E. , Kelders L.
Published: July 2012

Wave propagation in macroscopically inhomogeneous porous materials has received much attention in recent years. For planar configurations, the wave equation, derived from the alternative formulation of Biot’s theory of 1962, was reduced and solved recently: first in the case of rigid frame inhomogeneous porous materials and then in the case of inhomogeneous poroelastic materials in the framework of Biot’s theory. This paper focuses on the solution of the full wave equation in cylindrical coordinates for poroelastic tubes in which the acoustic and elastic properties of the poroelastic tube vary in the radial direction. The reflection coefficient is obtained numerically using the state vector (or the so-called Stroh) formalism and Peano series. This coefficient can then be used to straightforwardly calculate the scattered field. To validate the method of resolution, results obtained by the present method are compared to those calculated by the classical transfer matrix method in the case of a two-layer poroelastic tube. As an example, a long bone excited in the sagittal plane is considered. Finally, a discussion is given of ultrasonic time domain scattered field for various inhomogeneity profiles, which could lead to the prospect of long bone characterization.
Fiber-optic, cantilever-type acoustic motion velocity hydrophone
Authors: Cranch G. A. , Miller G. A. , Kirkendall C. K.
Published: July 2012

The interaction between fluid loaded fiber-optic cantilevers and a low frequency acoustic wave is investigated as the basis for an acoustic vector sensor. The displacements of the prototype cantilevers are measured with an integrated fiber laser strain sensor. A theoretical model predicting the frequency dependent shape of acoustically driven planar and cylindrical fiber-optic cantilevers incorporating effects of fluid viscosity is presented. The model demonstrates good agreement with the measured response of two prototype cantilevers, characterized with a vibrating water column, in the regime of Re ≥ 1. The performance of each cantilever geometry is also analyzed. Factors affecting the sensor performance such as fluid viscosity, laser mode profile, and support motion are considered. The planar cantilever is shown to experience the largest acoustically induced force and hence the highest acoustic responsivity. However, the cylindrical cantilever exhibits the smoothest response in water, due to the influence of viscous fluid damping, and is capable of two axis particle velocity measurement. These cantilevers are shown to be capable of achieving acoustic resolutions approaching the lowest sea-state ocean noise.
Frequency-radial duality based photoacoustic image reconstruction
Authors: Akramus Salehin S. M. , Abhayapala Thushara D.
Published: July 2012

Photoacoustic image reconstruction algorithms are usually slow due to the large sizes of data that are processed. This paper proposes a method for exact photoacoustic reconstruction for the spherical geometry in the limiting case of a continuous aperture and infinite measurement bandwidth that is faster than existing methods namely (1) backprojection method and (2) the Norton-Linzer method [S. J. Norton and M. Linzer, “Ultrasonic reflectivity imaging in three dimensions: Exact inverse scattering solution for plane, cylindrical and spherical apertures,” Biomedical Engineering, IEEE Trans. BME 28, 202–220 (1981)]. The initial pressure distribution is expanded using a spherical Fourier Bessel series. The proposed method estimates the Fourier Bessel coefficients and subsequently recovers the pressure distribution. A concept of frequency-radial duality is introduced that separates the information from the different radial basis functions by using frequencies corresponding to the Bessel zeros. This approach provides a means to analyze the information obtained given a measurement bandwidth. Using order analysis and numerical experiments, the proposed method is shown to be faster than both the backprojection and the Norton-Linzer methods. Further, the reconstructed images using the proposed methodology were of similar quality to the Norton-Linzer method and were better than the approximate backprojection method.
Wave based analysis of the Green’s function for a layered cylindrical shell
Authors: Magliula Elizabeth A. , McDaniel J. Gregory
Published: July 2012

Cylindrical shells composed of concentric layers may be designed to affect the way that elastic waves are generated and propagated, particularly when some layers are anisotropic. To aid the design process, the present work develops a wave based analysis of the Green’s function for a layered cylindrical shell in which the response is given as a sum of waves propagating in the axial coordinate. The analysis assumes linear Hookean materials for each layer. It uses finite element discretizations in the radial coordinate and Fourier series expansions in the circumferential coordinate, leading to linear equations in the axial wavenumber domain that relate shell displacements and forces. Inversion to the axial domain is accomplished via a state-space formulation that is evaluated using residue integration. The resulting expression for the Green’s function for each circumferential harmonic is a summation over the natural waves of the shell. The finite element discretization in the radial direction allows the approach to be used for arbitrarily thick shells. The approach is benchmarked to results from an isotropic shell and numerical examples are given for a shell composed of a fiber-reinforced material. The numerical examples illustrate the effect of fiber orientation on the Green’s function.
Acoustic analysis by spherical microphone array processing of room impulse responses
Authors: Khaykin Dima , Rafaely Boaz
Published: July 2012

Spherical microphone arrays have been recently used for room acoustics analysis, to detect the direction-of-arrival of early room reflections, and compute directional room impulse responses and other spatial room acoustics parameters. Previous works presented methods for room acoustics analysis using spherical arrays that are based on beamforming, e.g., delay-and-sum, regular beamforming, and Dolph-Chebyshev beamforming. Although beamforming methods provide useful directional selectivity, optimal array processing methods can provide enhanced performance. However, these algorithms require an array cross-spectrum matrix with a full rank, while array data based on room impulse responses may not satisfy this condition due to the single frame data. This paper presents a smoothing technique for the cross-spectrum matrix in the frequency domain, designed for spherical microphone arrays, that can solve the problem of low rank when using room impulse response data, therefore facilitating the use of optimal array processing methods. Frequency smoothing is shown to be performed effectively using spherical arrays, due to the decoupling of frequency and angular components in the spherical harmonics domain. Experimental study with data measured in a real auditorium illustrates the performance of optimal array processing methods such as MUSIC and MVDR compared to beamforming.
The influence of alcoholic intoxication on the fundamental frequency of female and male speakers
Authors: Baumeister Barbara , Heinrich Christian , Schiel Florian
Published: July 2012

This study investigates long-term features and utterance contours of fundamental frequency (f0) derived from the German Alcohol Language Corpus. The corpus comprises read, spontaneous, and command&control speech uttered by 148 speakers of both genders and various age groups when sober and intoxicated. f0 median, f0 range, and f0 contours are analyzed for intoxication and interactions with gender and age. Contours are compared both directly (root mean squared error, statistical correlation, or the Euclidean distance in the spectral space of the contour) and by parameterization of the contour using discrete cosine transform and the first and second moment of the lower contour spectrum. Results partly confirm earlier findings, i.e., f0 average and range are mostly raised with intoxication, and also suggest that the majority of speakers do not follow a general trend, but show idiosyncratic alterations to f0. f0 contours differ significantly with intoxication, but a more detailed analysis could not assign these changes to specific general form changes like decline or curvature. The results suggest that it is not possible to predict intoxication from f0 in a single model across different speakers. Instead a speaker-dependent model to account for the individual speaker behavior is proposed.
Asynchronous multiuser underwater acoustic communications (L)
Authors: Cho S. E. , Song H. C. , Hodgkiss W. S.
Published: July 2012

An asynchronous multiuser system is proposed to support multiple-access underwater communications without the use of code-division multiple-access or a feedback channel. The rich multipath channels experienced by spatially separated users will be sufficient to ensure separation of collided packets at the base station. The iterative receiver will employ a combination of adaptive time-reversal processing, matching pursuit, and successive interference cancellation in a block-wise fashion to achieve multiuser separability. Data collected during the KAM11 experiment are used to illustrate the system’s capability in a dynamic, time-varying environment.
The impact of early reflections on binaural cues
Authors: Gourévitch Boris , Brette Romain
Published: July 2012

Animals live in cluttered auditory environments, where sounds arrive at the two ears through several paths. Reflections make sound localization difficult, and it is thought that the auditory system deals with this issue by isolating the first wavefront and suppressing later signals. However, in many situations, reflections arrive too early to be suppressed, for example, reflections from the ground in small animals. This paper examines the implications of these early reflections on binaural cues to sound localization, using realistic models of reflecting surfaces and a spherical model of diffraction by the head. The fusion of direct and reflected signals at each ear results in interference patterns in binaural cues as a function of frequency. These cues are maximally modified at frequencies related to the delay between direct and reflected signals, and therefore to the spatial location of the sound source. Thus, natural binaural cues differ from anechoic cues. In particular, the range of interaural time differences is substantially larger than in anechoic environments. Reflections may potentially contribute binaural cues to distance and polar angle when the properties of the reflecting surface are known and stable, for example, for reflections on the ground.
Amplitude-dependent internal friction, hysteretic nonlinearity, and nonlinear oscillations in a magnesite resonator
Authors: Nazarov V. E. , Kolpakov A. B. , Radostin A. V.
Published: July 2012

The results of experimental and theoretical studies of low-frequency nonlinear acoustics phenomena (amplitude-dependent loss, resonance frequency shifts, and a generation of second and third harmonics) in a magnesite rod resonator are presented. Acceleration and velocity oscillograms of vibrations of the free boundary of the resonator caused by harmonic excitations were measured and analyzed. A theoretical description of the observed amplitude dependences was carried out within the framework of the phenomenological state equations that contain either of the two types of hysteretic nonlinearity (elastic and inelastic). The type of hysteresis and parameters of acoustic nonlinearity of magnesite were established from comparing the experimental measurements with the theoretical dependences. The values of the parameters were anomalously high even when compared to those of other strongly nonlinear polycrystalline materials such as granite, marble, limestone, sandstone, etc.
Scattering characteristics of Lamb waves from debondings at structural features in composite laminates
Authors: Ng Ching-Tai , Veidt Martin
Published: July 2012

This article investigates the scattering characteristics of Lamb waves from a debonding at a structural feature in a composite laminate. This study specifically focuses on the use of the low frequency fundamental antisymmetric (A0) Lamb wave as the incident wave for debonding detection. Three-dimensional finite element (FE) simulations and experimental measurements are used to investigate the scattering phenomena. Good agreement is obtained between the FE simulations and experimental results. Detailed parameter studies are carried out to further investigate the relationship between the scattering amplitudes and debonding sizes. The results show that the amplitude of the scattered A0 Lamb wave is sensitive to the debonding size, which indicates the potential of using the low frequency A0 Lamb wave as the interrogating wave for debonding detection and monitoring. The findings of the study provide improved physical insights into the scattering phenomena, which are important to further advance damage detection techniques and optimize transducer networks.
Detection of simultaneous modulation of interaural time and level differences: Effects of modulation rate and relative phase (L)
Authors: Furukawa Shigeto
Published: July 2012

The binaural system is known to be sluggish, i.e., unable to track modulations in interaural parameters even at a relatively slow rate. The present study evaluated the binaural system’s sensitivity to modulation phase rather than to modulation magnitude. The detectability of simultaneous modulations in interaural time and level differences with various relative phases were measured. It was found that for modulation rates up to 10–20 Hz, the detectability varied with the relative phase. This indicates that information about higher rates is lost at or below the level of cue integration.
Acoustic field and array response uncertainties in stratified ocean media
Authors: Hayward Thomas J. , Dhakal Sagar
Published: July 2012

The change-of-variables theorem of probability theory is applied to compute acoustic field and array beam power probability density functions (pdfs) in uncertain ocean environments represented by stratified, attenuating ocean waveguide models. Computational studies for one and two-layer waveguides investigate the functional properties of the acoustic field and array beam power pdfs. For the studies, the acoustic parameter uncertainties are represented by parametric pdfs. The field and beam response pdfs are computed directly from the parameter pdfs using the normal-mode representation and the change-of-variables theorem. For two-dimensional acoustic parameter uncertainties of sound speed and attenuation, the field and beam power pdfs exhibit irregular functional behavior and singularities associated with stationary points of the mapping, defined by acoustic propagation, from the parameter space to the field or beam power space. Implications for the assessment of orthogonal polynomial expansion and other methods for computing acoustic field pdfs are discussed.
Got a Light? Illuminating Lung Cancer
Authors: McAllister Sandra S.
Published: July 2012

New mouse models shed light on mechanisms of lung cancer progression and pinpoint a potential therapeutic target.
Bloodstream Infection Due to Mycoplasma arginini in an Immunocompromised Patient
Authors: Watanabe Mayumi , Hitomi Shigemi , Goto Miki , Hasegawa Yuichi
Published: July 2012

Mycoplasma arginini
, an organism usually recovered from mammals, was isolated from the blood of a febrile patient with advanced non-Hodgkin lymphoma. The patient's condition improved without administration of antimycoplasmal drugs. Simulation of blood culture showed that automated blood culture instruments may fail to detect the organism.
Complete Genome Sequences of Two
Pseudomonas aeruginosa
Temperate Phages, MP29 and MP42, Which Lack the Phage-Host CRISPR Interaction
Authors: Chung In-Young , Cho You-Hee
Published: July 2012

We report the complete genome sequence of two
Pseudomonas aeruginosa
phages MP29 and MP42. Their genomes are similar to those of
P. aeruginosa
temperate phages DMS3 and MP22, whose lysogens are impaired in swarming motilities, involving the host CRISPR loci. Both MP29 and MP42 lysogens, however, were proficient in swarming, suggesting the absence of the phage-host CRISPR interaction.
Complete Genome Sequence of
Celeribacter
Bacteriophage P12053L
Authors: Kang Ilnam , Jang Hani , Oh Hyun-Myung , Cho Jang-Cheon
Published: July 2012

The
Roseobacter
clade has been recognized as one of the abundant bacterial lineages in marine environments, which makes the characterization of bacteriophages infecting members of the clade important. Here we report the complete genome sequence of bacteriophage P12053L, which infects
Celeribacter
sp. strain IMCC12053, a member of the
Roseobacter
clade.