bluuebunny/crossref_metadata_2025 huggingface dataset:
The three-measurement two-calibration method for measuring the transfer matrix
Authors: Rodriguez S. , Gibiat V. , Lefebvre A. , Guilain Stephane
Published: May 2011

Extensive use of transfer matrices (TMs) is made in determining the acoustic properties of a duct and in in-duct acoustic propagation models in the automotive industry and for musical acoustics purposes. The experimental apparatuses of classical TM measurement methods feature two measurement heads. Two microphones are flush with the walls of each head. The pressure signals are processed following the transfer function method constructed on an analytical model of acoustic propagation in measurement heads. The present paper aims at presenting a measurement method based on a three-microphone experimental apparatus and on its acoustic calibration through two reference measurements: the three-measurement two-calibration method for measuring the TM (3M2C-TM). Two microphones are flush with the measurement head walls and one is in the cap closing one side of the measured duct. 3M2C-TM proved essential for an accurate measurement of the four TM elements of two different ducts: a cylindrical duct and an expansion chamber.
A channel-selection criterion for suppressing reverberation in cochlear implants
Authors: Kokkinakis Kostas , Hazrati Oldooz , Loizou Philipos C.
Published: May 2011

Little is known about the extent to which reverberation affects speech intelligibility by cochlear implant (CI) listeners. Experiment 1 assessed CI users’ performance using Institute of Electrical and Electronics Engineers (IEEE) sentences corrupted with varying degrees of reverberation. Reverberation times of 0.30, 0.60, 0.80, and 1.0 s were used. Results indicated that for all subjects tested, speech intelligibility decreased exponentially with an increase in reverberation time. A decaying-exponential model provided an excellent fit to the data. Experiment 2 evaluated (offline) a speech coding strategy for reverberation suppression using a channel-selection criterion based on the signal-to-reverberant ratio (SRR) of individual frequency channels. The SRR reflects implicitly the ratio of the energies of the signal originating from the early (and direct) reflections and the signal originating from the late reflections. Channels with SRR larger than a preset threshold were selected, while channels with SRR smaller than the threshold were zeroed out. Results in a highly reverberant scenario indicated that the proposed strategy led to substantial gains (over 60 percentage points) in speech intelligibility over the subjects’ daily strategy. Further analysis indicated that the proposed channel-selection criterion reduces the temporal envelope smearing effects introduced by reverberation and also diminishes the self-masking effects responsible for flattened formants.
Relative salience of envelope and fine structure cues in zebra finch song
Authors: Vernaleo Beth A. , Dooling Robert J.
Published: May 2011

Zebra finches produce a learned song that is rich in harmonic structure and highly stereotyped. More is generally known about how birds learn and produce this song than how they perceive it. Here, zebra finches were trained with operant techniques to discriminate changes in natural and synthetic song motifs. Results show that zebra finches are quite insensitive to changes to the overall envelope of the motif since they were unable to discriminate more than a doubling in inter-syllable interval durations. By contrast, they were quite sensitive to changes in individual syllables. A series of tests with synthetic song syllables, including some made of frozen noise and Schroeder harmonic complexes, showed that birds used a suite of acoustic cues in normal listening but they could also distinguish among syllables simply on the basis of the temporal fine structure in the waveform. Thus, while syllable perception is maintained by multiple redundant cues, temporal fine structure features alone are sufficient for syllable discrimination and may be more important for communication than previously thought.
Disrupting within-channel cues to comodulation masking release
Authors: Goldman Simon A. , Baer Thomas , Moore Brian C. J.
Published: May 2011

Comodulation masking release (CMR), assessed using a flanking-band (FB) paradigm, may reflect the contribution of both across- and within-channel cues when FBs are proximal to the signal frequency. This study examined the effect of disrupting within-channel cues based upon envelope beats at the output of an auditory filter centered at the signal frequency, using a method described by Richards [(1988) Hear. Res. 35, 47–58], here called “on-frequency band (OFB) reversal.” This removed regular beats for a pair of proximal FBs centered symmetrically about the OFB on a linear frequency scale (but not for a single FB that had the same center frequency as either of the constituent FBs in a pair) while maintaining the comodulation of individual noise bands that provides the basis for across-channel processes. OFB reversal consistently reduced CMR for proximal FB pairs—but not for a single FB or distal FB pair or when the FBs were presented in the opposite ear to the signal plus OFB—across a range of signal frequencies and for continuous and gated noise presentation. Simulations indicated that OFB reversal reduces the availability of within-channel cues based upon temporal fine structure and changes in envelope statistics.
Psychophysical tuning curves for frequencies below 100 Hz
Authors: Jurado Carlos , Pedersen Christian S. , Moore Brian C. J.
Published: May 2011

Psychophysical tuning curves (PTCs) were measured for sinusoidal signals with frequency fs = 31.5, 40, 50, 63, and 80 Hz, using sinusoidal and narrowband-noise maskers. For the former, conditions were included where a pair of beating tones was added to reduce the use of cues related to beats. Estimates of each subject’s middle-ear transfer function (METF) were obtained from equal-loudness contours measured from 20 to 160 Hz. With decreasing fs, the PTCs became progressively broadened and markedly asymmetrical, with shallow upper skirts and steep lower skirts. For the sinusoidal maskers, the tips were more irregular than for narrowband-noise maskers or when beating tones were added. For fs = 31.5 and 40 Hz, the tips of the PTCs always fell above fs. Allowing for the METF so as to infer underlying filter shapes resulted in flatter lower skirts, especially below 40 Hz, and reduced the frequency at the tips for fs between 31.5 and 50 Hz; however, the tips did not fall below 40 to 50 Hz. The bandwidths of the PTCs increased with decreasing fs below 80 Hz. However, bandwidths remained roughly constant if the METF was included as part of auditory filtering for frequencies below 40 Hz.
Note types and coding in Parid vocalizations: Thechick-a-deecall of the boreal chickadee (Poecile hudsonicus)
Authors: Moscicki Michele K. , Hoeschele Marisa , Bloomfield Laurie L. , Modanu Maria , Charrier Isabelle , Sturdy Christopher B.
Published: May 2011

An important first step in characterizing a vocalization is to classify, describe, and measure the elements of that vocalization. Here, this methodology is employed to study the chick-a-dee call of the boreal chickadee (Poecile hudsonicus). The note types (A, B, C, D, and Dh) in a sample of boreal chickadee calls are identified and described, spectral and temporal features of each note type are analyzed, and production phenomena in each note type are identified and quantified. Acoustic variability is compared across note types and individuals to determine potential features used for note-type and individual discrimination. Frequency measures appear to be the most useful features for identifying note types and individuals, though total duration may also be useful. Call syntax reveals that boreal chick-a-dee calls follow a general rule of note-type order, namely A-B-C-Dh-D, and that any note type in this sequence may be repeated or omitted. This work provides a thorough description of the boreal chickadee chick-a-dee call and will serve as a foundation for future studies aimed at elucidating this call’s functional significance within this species, as well as for studies comparing chick-a-dee calls across Poecile species.
Absorption of a rigid frame porous layer with periodic circular inclusions backed by a periodic grating
Authors: Groby J.-P. , Duclos A. , Dazel O. , Boeckx L. , Lauriks W.
Published: May 2011

The acoustic properties of a periodic rigid frame porous layer with multiple irregularities in the rigid backing and embedded rigid circular inclusions are investigated theoretically and numerically. The theoretical representation of the sound field in the structure is obtained using a combination of multipole method that accounts for the periodic inclusions and multi-modal method that accounts for the multiple irregularities of the rigid backing. The theoretical model is validated against a finite element method. The predictions show that the acoustic response of this structure exhibits quasi-total, high absorption peaks at low frequencies which are below the frequency of the quarter-wavelength resonance typical for a flat homogeneous porous layer backed by a rigid plate. This result is explained by excitation of additional modes in the porous layer and by a complex interaction between various acoustic modes. These modes relate to the resonances associated with the presence of a profiled rigid backing and rigid inclusions in the porous layer.
A generalized baleen whale call detection and classification system
Authors: Baumgartner Mark F. , Mussoline Sarah E.
Published: May 2011

Passive acoustic monitoring allows the assessment of marine mammal occurrence and distribution at greater temporal and spatial scales than is now possible with traditional visual surveys. However, the large volume of acoustic data and the lengthy and laborious task of manually analyzing these data have hindered broad application of this technique. To overcome these limitations, a generalized automated detection and classification system (DCS) was developed to efficiently and accurately identify low-frequency baleen whale calls. The DCS (1) accounts for persistent narrowband and transient broadband noise, (2) characterizes temporal variation of dominant call frequencies via pitch-tracking, and (3) classifies calls based on attributes of the resulting pitch tracks using quadratic discriminant function analysis (QDFA). Automated detections of sei whale (Balaenoptera borealis) downsweep calls and North Atlantic right whale (Eubalaena glacialis) upcalls were evaluated using recordings collected in the southwestern Gulf of Maine during the spring seasons of 2006 and 2007. The accuracy of the DCS was similar to that of a human analyst: variability in differences between the DCS and an analyst was similar to that between independent analysts, and temporal variability in call rates was similar among the DCS and several analysts.
Robust active noise control in the loadmaster area of a military transport aircraft
Authors: Kochan Kay , Sachau Delf , Breitbach Harald
Published: May 2011

The active noise control (ANC) method is based on the superposition of a disturbance noise field with a second anti-noise field using loudspeakers and error microphones. This method can be used to reduce the noise level inside the cabin of a propeller aircraft. However, during the design process of the ANC system, extensive measurements of transfer functions are necessary to optimize the loudspeaker and microphone positions. Sometimes, the transducer positions have to be tailored according to the optimization results to achieve a sufficient noise reduction. The purpose of this paper is to introduce a controller design method for such narrow band ANC systems. The method can be seen as an extension of common transducer placement optimization procedures. In the presented method, individual weighting parameters for the loudspeakers and microphones are used. With this procedure, the tailoring of the transducer positions is replaced by adjustment of controller parameters. Moreover, the ANC system will be robust because of the fact that the uncertainties are considered during the optimization of the controller parameters. The paper describes the necessary theoretic background for the method and demonstrates the efficiency in an acoustical mock-up of a military transport aircraft.
Low frequency deep ocean ambient noise trend in the Northeast Pacific Ocean
Authors: Chapman N. Ross , Price Andrea
Published: May 2011

Concern about effects of anthropogenic noise on marine life has stimulated new studies to establish present-day ocean noise levels and compare them to noise levels from previous times. This paper reports on the trend in low-frequency (10–400 Hz) ambient noise levels and presents measurements made using a calibrated multi-element volume array at deep ocean sites in the Northeast Pacific from 1978 to 1986. The experiments provided spectral noise levels as well as horizontal and vertical noise directionality. The data presented here provide evidence that the trend derived from 1960s data extended to around 1980, but has since continued at a lower rate.
Acoustic variability and social significance of calls in female Campbell’s monkeys (Cercopithecus campbelli campbelli)
Authors: Lemasson A. , Hausberger M.
Published: May 2011

Although the vocal repertoire of nonhuman primates is strongly constrained by genetic, a growing number of studies evidence socially determined flexibility. According to Snowdon et al. [Social Influences on Vocal Development (University Press, Cambridge, 1997), pp. 234–248], calls with a higher social function (affiliative or agonistic) would be expected to show more flexibility than lesser social calls. Owren and Rendall [Evol. Anthropol., 10, 58–71 (2001)] nuanced this by defending a structure-function relationship. Calls with particular acoustic properties, which directly influence the listener’s affect, would be less individually distinctive than calls involved in an affective conditioning process. These hypotheses were tested in Campbell’s monkeys using telemetric recordings. This is the first detailed description of female Campbell’s monkeys’ vocal repertoire emphasizing a possible relationship between social function and flexibility level. The vocal repertoire displayed an “arborescent” organization (call type, subtype, and variants). The highest number of subtypes and the greatest acoustic variability, within and among individuals, were found in calls associated with the highest affiliative social value. However, calls associated with agonism were the most stereotyped, whereas less social alarm calls were intermediate. This only partially validate the hypothesis of Snowdon et al. In accordance with Owren and Rendall’s hypotheses, the level of individual distinctiveness was minimum for noisy pulsed calls and maximum for calls involved in affiliative interactions.
Estimating the control parameters of an articulatory model from electromagnetic articulograph data
Authors: Toutios Asterios , Ouni Slim , Laprie Yves
Published: May 2011

Finding the control parameters of an articulatory model that result in given acoustics is an important problem in speech research. However, one should also be able to derive the same parameters from measured articulatory data. In this paper, a method to estimate the control parameters of the the model by Maeda from electromagnetic articulography (EMA) data, which allows the derivation of full sagittal vocal tract slices from sparse flesh-point information, is presented. First, the articulatory grid system involved in the model’s definition is adapted to the speaker involved in the experiment, and EMA data are registered to it automatically. Then, articulatory variables that correspond to measurements defined by Maeda on the grid are extracted. An initial solution for the articulatory control parameters is found by a least-squares method, under constraints ensuring vocal tract shape naturalness. Dynamic smoothness of the parameter trajectories is then imposed by a variational regularization method. Generated vocal tract slices for vowels are compared with slices appearing in magnetic resonance images of the same speaker or found in the literature. Formants synthesized on the basis of these generated slices are adequately close to those tracked in real speech recorded concurrently with EMA.
Distribution of standing-wave errors in real-ear sound-level measurements
Authors: Richmond Susan A. , Kopun Judy G. , Neely Stephen T. , Tan Hongyang , Gorga Michael P.
Published: May 2011

Standing waves can cause measurement errors when sound-pressure level (SPL) measurements are performed in a closed ear canal, e.g., during probe-microphone system calibration for distortion-product otoacoustic emission (DPOAE) testing. Alternative calibration methods, such as forward-pressure level (FPL), minimize the influence of standing waves by calculating the forward-going sound waves separate from the reflections that cause errors. Previous research compared test performance (Burke et al., 2010) and threshold prediction (Rogers et al., 2010) using SPL and multiple FPL calibration conditions, and surprisingly found no significant improvements when using FPL relative to SPL, except at 8 kHz. The present study examined the calibration data collected by Burke et al. and Rogers et al. from 155 human subjects in order to describe the frequency location and magnitude of standing-wave pressure minima to see if these errors might explain trends in test performance. Results indicate that while individual results varied widely, pressure variability was larger around 4 kHz and smaller at 8 kHz, consistent with the dimensions of the adult ear canal. The present data suggest that standing-wave errors are not responsible for the historically poor (8 kHz) or good (4 kHz) performance of DPOAE measures at specific test frequencies.
Structural-acoustic modeling for three-dimensional freefield and littoral environments with verification and validation
Authors: Dey S. , Sarkissian A. , Simpson H. , Houston B. H. , Bulat F. A. , Kraus L. , Saniga M. , Bucaro J. A.
Published: May 2011

This paper describes a high-order, finite-element-based, three-dimensional time-harmonic model for large-scale exterior structural-acoustics problems. It is applicable to both freefield and littoral environments. For the freefield case, the infinite exterior is treated as a homogeneous linear acoustic medium. For littoral applications, the water or air and the sediment domains are each treated as linear homogeneous, semi-infinite half-spaces with piecewise-constant properties. Both domains admit complex-valued wave speeds to enable the inclusion of damping. The finite element formulation uses a variational statement which naturally incorporates the transmission-condition at the water or air–sediment interface. The truncation of the infinite exterior is realized using an infinite-element for the freefield case, and the perfectly-matched-layer approximation for littoral applications. Computation of the farfield quantities is done based on an integral representation which, for the littoral cases, uses efficient approximations for the appropriate Green’s function. Numerical computations are presented for a series of progressively more complex problems, and are used to verify the model against analytic and other numerical solutions and validate it based on the experimental data for scattering from elastic scatterers as measured in freefield and sediment pool laboratory facilities.
Flocculation and sedimentation in suspensions using ultrasonic wave reflection
Authors: Chung Chul-Woo , Popovics John S. , Struble Leslie J.
Published: May 2011

This work was undertaken to help understand and interpret the ultrasonic wave reflection response of Portland cement paste as it transforms from a fluid-like suspension to a solid in the first hours after mixing. A high impact polystyrene buffer (delay line) was used to measure small changes in the P- and S-wave reflection coefficients. Two materials were studied: a non-hydrating colloidal alumina suspension whose microstructure was manipulated between dispersed and flocculated states by adjusting the pH and a coarse silica suspension that readily sedimented. The S-wave reflection coefficient clearly distinguished between dispersed and flocculated states. Sedimentation of particles in dispersed suspensions was distinguished using the P-wave reflection coefficient. Based on these findings, the observed P- and S-wave responses from hydrating Portland cement paste are interpreted in terms of flocculation and sedimentation processes.
Breaking away: Violation of distortion emission phase-frequency invariance at low frequencies
Authors: Dhar Sumitrajit , Rogers Abigail , Abdala Carolina
Published: May 2011

The phase versus frequency function of the distortion product otoacoustic emission (DPOAE) at 2f1 − f2 is approximately invariant at frequencies above 1.5 kHz in human subjects when recorded with a constant f2/f1. However, a secular break from this invariance has been observed at lower frequencies where the phase-gradient becomes markedly steeper. Apical DPOAEs, such as 2f1 − f2, are known to contain contributions from multiple sources. This experiment asked whether the phase behavior of the ear canal DPOAE at low frequencies is driven by the phase of the component from the distortion product (DP) region at 2f1 − f2, which exhibits rapid phase accumulation. Placing a suppressor tone close in the frequency to 2f1 − f2 reduced the contribution of this component to the ear canal DPOAE in normal-hearing adult human ears. When the contribution of this component was reduced, the phase behavior of the ear canal DPOAE was not altered, suggesting that the breaking from DPOAE phase invariance at low frequencies is an outcome of apical-basal differences in cochlear mechanics. The deviation from DPOAE phase invariance appears to be a manifestation of the breaking from approximate scaling symmetry in the human cochlear apex.
Effect of level on the discrimination of harmonic and frequency-shifted complex tones at high frequencies
Authors: Moore Brian C. J. , Sęk Aleksander
Published: May 2011

Moore and Sęk [J. Acoust. Soc. Am. 125, 3186–3193 (2009)] measured discrimination of a harmonic complex tone and a tone in which all harmonics were shifted upwards by the same amount in Hertz. Both tones were passed through a fixed bandpass filter and a background noise was used to mask combination tones. Performance was well above chance when the fundamental frequency was 800 Hz, and all audible components were above 8000 Hz. Moore and Sęk argued that this suggested the use of temporal fine structure information at high frequencies. However, the task may have been performed using excitation-pattern cues. To test this idea, performance on a similar task was measured as a function of level. The auditory filters broaden with increasing level, so performance based on excitation-pattern cues would be expected to worsen as level increases. The results did not show such an effect, suggesting that the task was not performed using excitation-pattern cues.
Comparative intelligibility investigation of single-channel noise-reduction algorithms for Chinese, Japanese, and English
Authors: Li Junfeng , Yang Lin , Zhang Jianping , Yan Yonghong , Hu Yi , Akagi Masato , Loizou Philipos C.
Published: May 2011

A large number of single-channel noise-reduction algorithms have been proposed based largely on mathematical principles. Most of these algorithms, however, have been evaluated with English speech. Given the different perceptual cues used by native listeners of different languages including tonal languages, it is of interest to examine whether there are any language effects when the same noise-reduction algorithm is used to process noisy speech in different languages. A comparative evaluation and investigation is taken in this study of various single-channel noise-reduction algorithms applied to noisy speech taken from three languages: Chinese, Japanese, and English. Clean speech signals (Chinese words and Japanese words) were first corrupted by three types of noise at two signal-to-noise ratios and then processed by five single-channel noise-reduction algorithms. The processed signals were finally presented to normal-hearing listeners for recognition. Intelligibility evaluation showed that the majority of noise-reduction algorithms did not improve speech intelligibility. Consistent with a previous study with the English language, the Wiener filtering algorithm produced small, but statistically significant, improvements in intelligibility for car and white noise conditions. Significant differences between the performances of noise-reduction algorithms across the three languages were observed.
Localization in speech mixtures by listeners with hearing loss
Authors: Best Virginia , Carlile Simon , Kopčo Norbert , van Schaik André
Published: May 2011

The ability of listeners with bilateral sensorineural hearing loss to localize a speech source in a multitalker mixture was measured. Five simultaneous words spoken by different talkers were presented over loudspeakers in a small room, and listeners localized one target word. Errors were significantly larger in this group compared to a control group with normal hearing. Localization of the target presented alone was not different between groups. The results suggest that hearing loss does not impair spatial hearing per se, but degrades the spatial representation of multiple simultaneous sounds.
Minke whale (Balaenoptera acutorostrata) boings detected at the Station ALOHA Cabled Observatory
Authors: Oswald Julie N. , Au Whitlow W. L. , Duennebier Fred
Published: May 2011

Minke whales (Balaenoptera acutorostrata) in the tropical North Pacific are elusive and difficult to detect visually. The recent association of a unique sound called the “boing” to North Pacific minke whales has made it possible to use passive acoustics to investigate the occurrence of this species in Hawaiian waters. One year of recordings (17 February 2007–18 February 2008) made at the Station ALOHA Cabled Observatory were examined to investigate the characteristics of boings and temporal patterns in their occurrence at this site, located 100 km north of Oahu. Characteristics of boings exhibited low variability. Pulse repetition rate and duration measurements matched those for “central” or “Hawaii” boing types. Boings were detected from October until May, with a peak in March. Although no boings were detected from June to September, the absence of boings does not necessarily indicate the absence of minke whales. Significant diel variation in boing rate was not observed. The absence of a diel pattern in boing production suggests that day- or night-time acoustic surveys are equally acceptable methods for studying minke whale occurrence. Future research should include efforts to determine what other sounds are produced by minke whales in this area, and which age/sex classes produce boings.
ACOUSTICAL STANDARDS NEWS
Authors: Blaeser Susan B. , Schomer Paul D.
Published: May 2011

American National Standards (ANSI Standards) developed by Accredited Standards Committees S1, S2, S3, and S12 in the areas of acoustics, mechanical vibration and shock, bioacoustics, and noise, respectively, are published by the Acoustical Society of America (ASA). In addition to these standards, ASA publishes catalogs of Acoustical Standards, both National and International. To receive copies of the latest Standards catalogs, please contact Susan B. Blaeser.

Comments are welcomed on all material in Acoustical Standards News.

This Acoustical Standards News section in JASA, as well as the National and International Catalogs of Acoustical Standards, and other information on the Standards Program of the Acoustical Society of America, are available via the ASA home page: http://acousticalsociety.org.
Protein Kinases Curb Cell Death
Authors: Filhol Odile , Cochet Claude
Published: May 2011

Phosphorylation of procaspases and their substrates by protein kinase CK2 puts the brakes on cell death.
PIP-Influenced Transcription
Authors: VanHook Annalisa M.
Published: May 2011

Lipid binding directly modulates the activity of the yeast transcription factor Tup1.
Understanding Wnt’s Role in Osteoarthritis
Authors: Gough Nancy R.
Published: May 2011

Research with chondrocytes suggests a mechanism by which activation or inhibition of Wnt signaling can produce dedifferentiation.
Immune Response of Chicken Gut to Natural Colonization by Gut Microflora and to Salmonella enterica Serovar Enteritidis Infection
Authors: Crhanova Magdalena , Hradecka Helena , Faldynova Marcela , Matulova Marta , Havlickova Hana , Sisak Frantisek , Rychlik Ivan
Published: May 2011

In commercial poultry production, there is a lack of natural flora providers since chickens are hatched in the clean environment of a hatchery. Events occurring soon after hatching are therefore of particular importance, and that is why we were interested in the development of the gut microbial community, the immune response to natural microbial colonization, and the response to
Salmonella enterica
serovar Enteritidis infection as a function of chicken age. The complexity of chicken gut microbiota gradually increased from day 1 to day 19 of life and consisted of
Proteobacteria
and
Firmicutes
. For the first 3 days of life, chicken cecum was protected by increased expression of chicken β-defensins (i.e., gallinacins 1, 2, 4, and 6), expression of which dropped from day 4 of life. On the other hand, a transient increase in interleukin-8 (IL-8) and IL-17 expression could be observed in chicken cecum on day 4 of life, indicating physiological inflammation and maturation of the gut immune system. In agreement, the response of chickens infected with
S
. Enteritidis on days 1, 4, and 16 of life shifted from Th1 (characterized mainly by induction of gamma interferon [IFN-γ] and inducible nitric oxide synthase [iNOS]), observed in younger chickens, to Th17, observed in 16-day-old chickens (characterized mainly by IL-17 induction). Active modification of chicken gut microbiota in the future may accelerate or potentiate the maturation of the gut immune system and increase its resistance to infection with different pathogens.
Histopathological alterations of the parathyroid glands in haemodialysis patients with secondary hyperparathyroidism refractory to cinacalcet hydrochloride
Authors: Sumida Keiichi , Nakamura Michio , Ubara Yoshifumi , Marui Yuji , Tanaka Kiho , Takaichi Kenmei , Tomikawa Shinji , Inoshita Naoko , Ohashi Kenichi
Published: May 2011

Background

Cinacalcet treatment for secondary hyperparathyroidism (SHPT) has demonstrated parathyroid size regression and morphological changes, such as cystic degeneration and hypovascularisation, on ultrasonography.; However, there have been very few reports regarding the histopathological alterations of hyperplastic parathyroid glands in patients with SHPT after administration of cinacalcet. The aim of this study was to elucidate the effects of cinacalcet for histopathological alterations on the parathyroid glands.

Methods

A total of 92 hyperplastic parathyroid glands were obtained from 24 dialysis patients with severe SHPT who underwent total parathyroidectomy and were enrolled in this study. Patients were divided into those treated with and without cinacalcet (cinacalcet group and conventional group, respectively; both n=12). The areas of oxyphil cells, cystic degeneration, haemorrhagic changes and haemosiderin deposition were assessed semiquantitatively.

Results

Total maximal parathyroid gland weight and maximal-to-minimal parathyroid gland weight ratio were significantly higher in the cinacalcet group compared with the conventional group (1798.7±1658.3 mg vs 764.2±471.1 mg, p=0.018, 15.8±13.9 vs p=0.047, 6.6±4.2, respectively). Significant increases were observed in oxyphil cell area (61.7%±17.1% vs 36.7%±15.6%, p=0.001) and haemosiderosis score (1.50±1.24 vs 0.42±0.51, p=0.029) in the former rather than the latter group.

Conclusions

These results suggest that cinacalcet may induce specific qualitative alterations of hyperplastic parathyroid glands in patients with severe SHPT.
Excessive dynamic airway collapse for the internist: new nomenclature or different entity?
Authors: Kalra Ankur , Abouzgheib Wissam , Gajera Mithil , Palaniswamy Chandrasekar , Puri Nitin , Dellinger Richard Phillip
Published: May 2011

Excessive dynamic airway collapse (EDAC) refers to abnormal and exaggerated bulging of the posterior wall within the airway lumen during exhalation. This condition is pathological if the reduced airway lumen is <50% of the normal. It is a relatively new disease entity that is recognised more easily now with the increased use of multi-detector row CT. EDAC is often asymptomatic and diagnosed incidentally. Although the term excessive dynamic airway collapse is often used interchangeably with tracheobronchomalacia, both entities represent morphologically and physiologically distinct processes. Considering the confusion between the two entities, the prevalence of stand-alone EDAC remains unclear. The prevalence of tracheobronchomalacia and EDAC depends upon the patient population, associated comorbidities and underlying aetiologies, diagnostic tools used and criteria used to define the airway collapse. This review defines EDAC and describes its pathophysiology, precipitating factors, associated symptoms and potential treatments.
Hypertrophic feline muscular dystrophy: diagnostic overview and a novel immunohistochemical diagnostic method using formalin‐fixed tissue
Authors: Blunden A. S. , Gower S.
Published: May 2011

This paper describes a case of hypertrophic feline muscular dystrophy (HFMD) in the UK. The cat under investigation died unexpectedly following routine vaccination, and postmortem investigation revealed myopathy, particularly affecting the diaphragm as well as multiple skeletal muscles. The right lung lobes were also partially collapsed and this was considered secondary to the effect of the muscular dystrophy. Pathological and immunohistochemical findings are described, macroscopic and microscopic findings are compared with other recorded cases in the literature and a diagnostic overview of HFMD is given. Possible causes of death are also discussed and a novel immunohistochemical method of demonstrating dystrophin deficiency using formalin‐fixed tissue is described.
Analysis of the bacterial community within carrot wash water
Authors: Hausdorf Lena , Fröhling Antje , Schlüter Oliver , Klocke Michael
Published: May 2011

Vegetables are washed after harvest to remove unwanted organic and inorganic particles, but wash water contaminated with certain pathogenic microorganisms can potentially contaminate produce. In this study, the microbial diversity of wash water was analyzed in samples taken from a carrot-processing facility. A 16S rRNA gene library with 427 clones was constructed and analyzed by amplified rDNA restriction analysis. For taxonomic classification, the 16S rRNA gene nucleotide sequences of 94 amplified rDNA restriction analysis fingerprints were determined. Each fingerprint indicates a distinct group of microorganisms. The nucleotide sequences were assigned to corresponding reference species. The most prevalent genus was Tolumonas , with 26% of the clones, followed by Acinetobacter and Flacobacterium , with 11% each. The latter two genera contain species that are known to cause nosocomial infections. The fourth most common genus was Arcobacter , comprising 9% of all clones. Some species of Arcobacter are considered to be emerging food pathogens, mainly associated with the contamination of meat products. So far, they have not been considered as contaminants of fresh produce. Based on the sequence data, an Arcobacter-specific PCR assay was developed to facilitate the detection of vegetable-associated Arcobacter strains.
Rhizosphere soil microorganism populations and community structures of different watermelon cultivars with differing resistance to Fusarium oxysporum f. sp. niveum
Authors: An Meijun , Zhou Xingang , Wu Fengzhi , Ma Yafei , Yang Ping
Published: May 2011

Fusarium wilt is an increasingly serious disease of watermelon that reduces crop productivity. Changes in microorganism populations and bacterial and fungal community structures in rhizosphere soil of watermelon cultivars resistant or susceptible to Fusarium oxysporum f. sp. niveum were investigated using a plate culture method and PCR–DGGE analysis. Plate culture showed that populations of culturable bacteria and actinomycetes were more abundant in the rhizosphere of the resistant watermelon cultivar than the susceptible cultivar, but the fungi population had the opposite pattern. Populations of Penicillium , Fusarium , and Aspergillus were significantly lower in the resistant cultivar than the susceptible cultivar at the fruiting and uprooting stages (p < 0.05). Pattern matching analysis generated the dendrogram of the DGGE results indicating the relatedness of the different resistant watermelon cultivars and their corresponding rhizosphere microbial communities. Further sequencing analysis of specific bands from DGGE profiles indicated that different groups of bacteria and fungi occurred in the rhizosphere of different watermelon cultivars. Our results demonstrated that plant genotype had a significant impact on soil microbial community structure, and the differences in the rhizosphere microbial community may contribute to the differences in resistance to F. oxysporum f. sp. niveum.
Local bacteriophage isolates showed anti-Escherichia coliO157:H7 potency in an experimental ligated rabbit ileal loop model
Authors: Alam Muntasir , Akhter Marufa Zerin , Yasmin Mahmuda , Ahsan Chowdhury Rafiqul , Nessa Jamalun
Published: May 2011

Escherichia coli O157:H7 is considered among the most important recently emerged food-borne bacteria causing severe hemorrhagic diarrhea. Antibiotic treatment is not recommended as a prospective curative agent against this pathogen. Therefore, potency assessment of the local lytic phage isolates infecting E. coli O157:H7 as an alternate remedy to antibiotics was the principal concern of this study. Phage isolates against E. coli O157:H7 were checked by polymerase chain reaction for the presence of the virulence genes stx1 and stx2, and the safe phages were further screened in vitro for their capacity as biocontrol agents. Two bacteriophage strains, namely PAH6 and P2BH2, that had expressed potential antibacterial activity (P < 0.05) in vitro were selected for in vivo testing in ligated rabbit ileal loop models. Both phage isolates were capable of decreasing fluid accumulation in rabbit ileal loops along with reducing bacterial growth (r = 0.992). Combined application of the phages was found most satisfactory, reducing seven log cycles of bacterial growth. Consistent results in both in vivo and in vitro experiments demonstrate the applicability of bacteriophages as a rapid response tool against E. coli O157:H7. To our knowledge, this is the first successful application of the rabbit ileal loop test for therapeutic evaluation of bacteriophages.
Validation and standardization of IS900 and F57 real-time quantitative PCR assays for the specific detection and quantification ofMycobacterium aviumsubsp.paratuberculosis
Authors: Sidoti Francesca , Banche Giuliana , Astegiano Sara , Allizond Valeria , Cuffini Anna Maria , Bergallo Massimiliano
Published: May 2011

Mycobacterium avium subsp. paratuberculosis (Map) is the causative agent of Johne’s disease and may contribute to the onset and development of Crohn’s disease in humans. Rapid detection of Map is fundamental because of its reported isolation from pasteurized milk and its potential for transmission through environmental sources. In this study, we developed two independent real-time quantitative PCR assays targeting the IS900 genetic insertion sequence and the F57 sequence, which proved capable of detecting and quantifying Map DNA. Validation and standardization of the developed methods were performed by evaluating diagnostic trueness, precision, and accuracy of the techniques. Specificity of the IS900 and F57 methods was verified in both in silico and experimental studies. The assays were found to be very accurate and precise with high repeatability and reproducibility. Moreover, the two real-time assays were very specific for Map, discriminating most of mycobacterial and nonmycobacterial species.
Active immunization againstPneumocystis cariniiwith p55-v3 DNA vaccine in rats
Authors: Feng Yanmei , Guo Shuliang , Jiang Tao , Han Xiaoli , Liu Ping , Wu Tingting , Luo Yongai
Published: May 2011

Pneumocystis pneumonia (PCP) occurs predominately in patients with impaired immunity. Because standard PCP chemoprophylaxis and chemotherapies have limitations, immunotherapy, particularly vaccination, offers an attractive alternative approach for PCP prevention and treatment. The goal of this study was to evaluate the potential of DNA vaccines targeting two closely related antigens, p55-v0 and p55-v3, in an immunosuppressed rat PCP model. We found that immunization with p55-v0 and p55-v3 DNA vaccines afforded a similar level of protection to rats against PCP, as evidenced by significant reductions in organism burdens, improved histological scores, and lower lung weight to body weight ratios. Additionally, vaccination elicited both cellular and humoral immunity in immunosuppressed rats. Our data suggest the potential of p55 DNA vaccines to protect against PCP in rats. Future work should focus on epitope mapping and identifying protective moieties in each gene.
Cdr2p contributes to fluconazole resistance in Candida dubliniensis clinical isolates
Authors: Borecká Silvia , Pinjon Emmanuelle , Sullivan Derek J. , Kuchler Karl , Blaško Jaroslav , Kulková Naďa , Bujdáková Helena
Published: May 2011

The development of resistance to azole antifungals used in the treatment of fungal infections can be a serious medical problem. Here, we investigate the molecular mechanisms associated with reduced susceptibility to fluconazole in clinical isolates of Candida dubliniensis , showing evidence of the trailing growth phenomenon. The changes in membrane sterol composition were studied in the presence of subinhibitory fluconazole concentrations. Despite lanosterol and eburicol accumulating as the most prevalent sterols after fluconazole treatment, these ergosterol precursors still support growth of Candida isolates. The overexpression of ABC transporters was demonstrated by immunoblotting employing specific antibodies against Cdr1p and Cdr2p. The presence of a full-length 170 kDa protein Cdr1p was detected in two isolates, while a truncated form of Cdr1p with the molecular mass of 85 kDa was observed in isolate 966/3(2). Notably, Cdr2p was detected in this isolate, and the expression of this transporter was modulated by subinhibitory concentrations of fluconazole. These results suggest that C. dubliniensis can display the trailing growth phenomenon, and such isolates express similar molecular mechanisms like that of fluconazole-resistant isolates and can therefore be associated with recurrent infections.
A new method for multiple gene inactivations in Bacillus subtilis 168, producing a strain free of selectable markers
Authors: Zhang Chong , Zhang Xiaohui , Yao Zhengying , Lu Yaping , Lu Fengxia , Lu Zhaoxin
Published: May 2011

This study describes a novel method for repeated gene inactivation in Bacillus subtilis 168. A B. subtilis strain (BS-PS) that is conditionally auxotrophic for lysine was obtained by replacing the PlysA promoter with the Pspac promoter. The homologous recombination integration vector PLC-T was constructed to contain lacI, which encodes a Pspac promoter repressor, and the chloromycetin resistance gene. Target genes were manipulated by generating an insertion sequence with two homologous arms and the target gene in PLC-T to create a specific integrating vector. Integration into the BS-PS chromosome occurred by a single crossover at either of the two homologous arms. The resulting transitional strain (BS-PS-PI) was chloromycetin resistant and lysine auxotrophic and had an unstable genome structure because of the duplication. Excision of lacI and chloromycetin resistance gene was achieved by a second single crossover at the duplication. Recovery of a lysine prototroph functioned as counter-selection and was identified by PCR. In this work, we inactivated nprE and aprE, two protease genes secreted by B. subtilis 168 free of selectable markers.
ON THE COMPLEXITY OF THE SUCCESSIVITY RELATION IN COMPUTABLE LINEAR ORDERINGS
Authors: DOWNEY ROD , LEMPP STEFFEN , WU GUOHUA
Published: May 2011

In this paper, we solve a long-standing open question (see, e.g. Downey [6, Sec. 7] and Downey and Moses [11]), about the spectrum of the successivity relation on a computable linear ordering. We show that if a computable linear ordering [Formula: see text] has infinitely many successivities, then the spectrum of the successivity relation is closed upwards in the computably enumerable Turing degrees. To do this, we use a new method of constructing [Formula: see text]-isomorphisms, which has already found other applications such as Downey, Kastermans and Lempp [9] and is of independent interest. It would seem to promise many further applications.
A 2-MINIMAL NON-GL2DEGREE
Authors: CAI MINGZHONG
Published: May 2011

We show that there is a non-GL2degree which is a minimal cover of a minimal degree. This answers a question by Lerman.
ON THE SUPERMODULARITY OF HOMOGENEOUS OLIGOPOLY GAMES
Authors: DRIESSEN THEO , MEINHARDT HOLGER
Published: May 2011

The main purpose is to prove the supermodularity (convexity) property of a cooperative game arising from an economical situation. The underlying oligopoly situation is based on a linear inverse demand function as well as linear cost functions for the participating firms. The characteristic function of the so-called oligopoly game is determined by maximizing, for any cartel of firms, the net profit function over the feasible production levels of the firms in the cartel, taking into account their individual capacities of production and production technologies. The (rather effective) proof of the supermodularity of the characteristic function of the oligopoly game relies on the use of maximizers for the relevant maximization problems. A similar proof technique will be reviewed for a related cooperative oligopoly game arising from a slightly modified oligopoly situation where the production technology of the cartel is determined by the most efficient member firm.
NONLINEAR DUOPOLY GAMES WITH ADVERTISEMENT REVISITED
Authors: MATSUMOTO AKIO , SZIDAROVSZKY FERENC
Published: May 2011

This study reconsiders a duopoly model with advertisement introduced earlier by Ahmed, Agiza and Hassan [1999]. It demonstrates three major findings. The first is that the model can be destabilized via either flip bifurcation or Hopf bifurcation. The second is that a half-pitchfork bifurcation of the output occurs when the advertisement dynamics is periodic and the nonlinearity of the output dynamics becomes stronger. Finally the third is that the existence of attractor and the coexistence of attracting sets are the main features of the model when it is locally unstable.
A NOTE ON THE WEAK SEQUENTIAL CORE OF DYNAMIC TU GAMES
Authors: HABIS HELGA , JEAN-JACQUES HERINGS P.
Published: May 2011

This paper addresses a problem with an argument in Kranich, Perea, and Peters [2005] supporting their definition of the Weak Sequential Core and their characterization result. We also provide the remedy, a modification of the definition, to rescue the characterization.
SINGULAR LIMITS FOR 2-DIMENSIONAL ELLIPTIC PROBLEM WITH EXPONENTIALLY DOMINATED NONLINEARITY AND SINGULAR DATA
Authors: BARAKET SAMI , BEN OMRANE INES , OUNI TAIEB , TRABELSI NIHED
Published: May 2011

We study existence of solutions with singular limits for a 2-dimensional semilinear elliptic problem with exponential dominated nonlinearity and a singular source term given by Dirac masses, imposing Dirichlet boundary condition. This paper extends previous results obtained in [3, 8]. We mainly use the method of domain decomposition.