bluuebunny/crossref_metadata_2025 huggingface dataset:
Localization of CD9 Molecule on Bull Spermatozoa: Its Involvement in the Sperm–Egg Interaction
Authors: Antalíková J , Jankovičová J , Simon M , Cupperová P , Michalková K , Horovská Ľ
Published: March 2015

Contents

Tetraspanin CD9 is one of the egg membrane proteins known to be essential in fertilization process. The presence and localization of CD9 molecule in spermatozoa and its possible function in reproduction are still unclear. In our study, we describe the localization of CD9 on bull spermatozoa. In the immunofluorescence assay, the positive signal has been observed in the high proportion of sperm cells as a fine grains either on the apical part or through the entire anterior region of sperm head. CD9 recognized by monoclonal antibody IVA‐50 was detected on freshly ejaculated (83.4 ± 3.7%) and frozen‐thawed (84.3 ± 2.3%) sperm. The same reaction pattern was observed on sperm capacitated for 1 h, 2 h, 3 h and 4 h (83.6 ± 2.0%; 84.0 ± 1.5%; 85.7 ± 0.8%; 77.5 ± 10.8%). The presence of CD9 exclusively on plasma membrane of the bovine sperm has been detected by Western blot analysis of the protein fractions after the discontinuous sucrose gradient fractionation of the bull sperm. Moreover, probable role of the sperm CD9 molecule in fertilization process of cattle has been suggested as sperm treatment with anti‐CD9 antibody significantly reduced (by 25%, p ≤ 0.001) the number of fertilized oocytes compared to control group in fertilization assay in vitro.
Reproductive Performance and Reconception of Nellore Cows According to Their Pure‐ or Cross‐Bred Calves
Authors: Rodrigues WB , Wechsler FS , Nogueira E
Published: March 2015

Contents

The objective of the present research was to evaluate the effect of a calf's genetic group on the productive and reproductive efficiency of its Nellore dam. Fixed‐time artificial insemination was applied to 800 cows using semen extracted from Nellore, Simmental and Angus Red bulls. Four hundred eleven cows calved, producing 119 Nellore, 103 ½Simmental–½Nellore and 189 ½Nellore–½Angus Red calves. The second mating period, which paired Nellore cows with Simmental bulls, was initiated 10 days after parturitions began and lasted for 5 months. Based on the two successive parturitions, the cumulative parturition rate for calving periods of 3, 4 and 5 months was calculated. Although no significant difference was observed for birth weight among the genetic groups, cross‐bred calves weighed, on average, 10% more than did pure‐bred calves at the age of 205 days. Nellore dams experienced a gestation period that was 7 days longer than did the cross‐bred dams, and the former showed a higher parturition rate at 90 and 120 days of the calving season, but not at 150 days (calving rates of 80.6, 76.4 and 76.2% for mothers of Nellore, ½Nellore–½Angus Red and ½Nellore–½Simmental, respectively, p > 0.05). At 90 and 120 days, Nellore dams produced more kg of calf per mated dam. In conclusion, in a short breeding season, Nellore dams nursing pure‐bred Nellore calves were found to have a higher biological efficiency compared with Nellore dams nursing cross‐bred calves.
Expression of Mitochondria‐Associated Genes (PPARGC1A,NRF‐1,BCL‐2 and BAX) in Follicular Development and Atresia of Goat Ovaries
Authors: Zhang G , Wan Y , Zhang Y , Lan S , Jia R , Wang Z , Fan Y , Wang F
Published: March 2015

Contents

Most follicles undergo atresia during the developmental process. Follicular atresia is predominantly regulated by apoptosis of granulosa cells, but the mechanism underlying apoptosis via the mitochondria‐dependent apoptotic pathway is unclear. We aimed to investigate whether the mitochondria‐associated genes peroxisome proliferator‐activated receptor‐gamma, coactivator1‐alpha (PPARGC1A), nuclear respiratory factor‐1 (NRF‐1), B‐cell CLL/lymphoma 2 (BCL‐2) and BCL2‐associated X protein (BAX) played a role in follicular atresia through this pathway. The four mitochondria‐associated proteins (PGC‐1α, which are encoded by the PPARGC1A gene, NRF‐1, BCL‐2 and BAX) mainly expressed in granulosa cells. The mRNA and protein levels of PPARGC1A/PGC‐1α and NRF‐1 in granulosa cells increased with the follicular development. These results showed that these genes may play a role in the regulation of the follicular development. In addition, compared with healthy follicles, the granulosa cell in atretic follicles had a reduced expression of NRF‐1, increased BAX expression and increased ratio of BAX to BCL‐2 expression. These results suggested that changes of the mitochondria‐associated gene expression patterns in granulosa cells may lead to follicular atresia during goat follicle development.
Formal independence of regulatory agencies andVarieties ofCapitalism: A case of institutional complementarity?
Authors: Guardiancich Igor , Guidi Mattia
Published: March 2015

TheVarieties ofCapitalism literature posits that national economic institutions reflect the mode of coordination of a country's market actors. Despite the importance of this claim and a rich literature on the emergence of regulatory capitalism, few studies test such prediction forIndependentRegulatoryAgencies (IRAs). This article connects the two fields of research by analysing the impact of economic coordination on the formal independence ofIRAs. The results show that, beyond issues of credible commitment and policy stability, the collective action capacity of market actors matters. In particular, regulators in Coordinated Market Economies enjoy less independence than in Liberal Market Economies, while intermediate regimes grantIRAsthe least autonomy. The policy implications are nontrivial. Similar to other macroeconomic institutions, inappropriate combinations of economic coordination andIRAindependence may engenderPareto‐suboptimal regulatory solutions. In such cases, policymakers should reconsider the rules governing national regulators.
Making sense of the legal and judicial architectures of regional trade agreements worldwide
Authors: Duina Francesco
Published: March 2015

Regional trade agreements (RTAs) constitute one of the most important elements of the international economic order. Researchers have accordingly embarked on comparative analyses of their design. Yet one fundamental question remains unanswered: how have officials in different RTAs responded to the challenge of regulatory misalignments among the member states? In this article, I turn to 10 of the most established RTAs in the world and document three types of responses. Some RTAs rely on the principle of mutual recognition or references to existing international standards; the same agreements also rely on technical dispute resolution mechanisms. Other RTAs, by contrast, make use of extensive harmonization and permanent courts charged with interpreting law. Yet a third group exhibits a hybrid design. This heterogeneity in legislative and judicial design invites explanation. I show that there is a remarkable correspondence between the legal traditions of the member states (common vs. civil law) and the design of RTAs. This correspondence undermines the claims of world polity theorists about the nature of the international order, but is consistent with other strands of sociological institutionalism and certain elements of rationalist and neoliberal institutionalism. I conclude by reflecting on the implications of different RTA designs for the regulation of everyday life in the member states, the World Trade Organization as an international regulatory body, and national sovereignty and democracy.
Unloading‐Based Stiffness Characterisation of Cement Pastes During the Second, Third and Fourth Day After Production
Authors: Karte P. , Hlobil M. , Reihsner R. , Dörner W. , Lahayne O. , Eberhardsteiner J. , Pichler B.
Published: March 2015

The stiffness evolution of binder ‘cement paste’ is triggering the stiffness of concrete. In the engineering practice, concrete formworks are typically removed 24 h after production. This underlines that knowledge on mechanical properties of cementitious materials during the second, third and fourth day after production is of high relevance for the ongoing construction process. This provides the motivation to perform early‐age stiffness characterisation on hydrating cement pastes, by means of the following three test methods. Unloading modulus is determined using a novel setup for non‐destructive uniaxial compression testing including overdetermined deformation measurements. Dynamic Young's moduli are obtained from ultrasonics experiments. Isothermal differential calorimetry allows for linking the observed temporal evolution of early‐age stiffness to the hydration degree of cement. Pastes with three different compositions are investigated, defined in terms of the initial water‐to‐cement mass ratio w/c and the initial water‐to‐solid (binder) mass ratio w/s. Pure cement pastes exhibit w/c = w/s = 0.50 and w/c = w/s = 0.42, respectively. A fly ash‐blended cement paste refers to a cement mass replacement level of 16%, and this is related to w/c = 0.50 and w/s = 0.42. Both unloading moduli and dynamic Young's moduli of all three materials increase practically linearly with increasing hydration degree, in the investigated regime of hydration degrees ranging from 40 to 60%. Fly ash does not contribute significantly to the early‐age hydration of the material, i.e. it represents a quasi‐inert part of the material's microstructure, exhibiting a significant stiffening effect.
Performance of Liaison XL automated immunoassay platform for blood‐borne infection screening on hepatitis B, hepatitis C, HIV 1/2, HTLV 1/2 and Treponema pallidum serological markers
Authors: Malm K. , Kragsbjerg E. , Andersson S.
Published: March 2015

Objectives

Aim of the study was to evaluate performance of a new fully automated platform, DiaSorin‐LIAISON® XL (DiaSorin S.p.A, Vercelli, Italy), in blood donor screening, specifically for hepatitis B surface antigen (HBsAg), hepatitis B core antibodies (anti‐HBc), hepatitis C antibodies (anti‐HCV), HIV p24 antigen, HIV antibodies, human T‐lymphotropic virus types 1 and 2 (HTLV‐1/2) and Treponema pallidum antibodies.

Background

In screening for such viral and bacteriological blood‐borne infections, sensitivity and specificity are of utmost importance.

Methods

Sensitivity was evaluated using selected panels of samples previously analysed on the Abbott Architect immunoanalyser (Abbott Laboratories, Abbott Park, IL, USA) – the gold standard for this evaluation. These samples were confirmed positive for HBsAg, anti‐HBc, anti‐HCV, HIV Ag/Ab, anti‐HTLV‐1/2 and antibodies to T. pallidum, respectively. Specificity analysis was assessed by analysing blood donor samples previously run on the Architect platform and found non‐reactive for each marker. A total of 1·100 donor samples (both new and regular donors) were tested. Previously, non‐specific reactive samples were also run for every tested marker, as well as samples with autoimmune antibodies and antibodies to other infections.

Results

Three hundred seventy‐eight samples positive for the tested markers (HBsAg n = 51, anti‐HBc n = 52, anti‐HCV n = 75, anti‐Treponema n = 55, anti‐HIV‐1 n = 79, anti‐HIV‐2 n = 25, anti‐HIV 1/2 n = 3, anti‐HTLV‐1 n = 28 anti‐HTLV‐2 n = 10) were tested and found positive, suggesting a high sensitivity. A number of 342–1100 negative blood donors (depending on marker) have been tested, with very good specificity for the markers tested, ranging between 99·5 and 100%, respectively.

Conclusions

The LIAISON® XL platform demonstrated very high sensitivity for the markers tested and the specificity necessary to fulfil the stringent requirements for blood donor screening.
Mechanical and Microstructural Investigation of the Cyclic Behavior of Human Amnion
Authors: Perrini Michela , Mauri Arabella , Ehret Alexander Edmund , Ochsenbein-Kölble Nicole , Zimmermann Roland , Ehrbar Martin , Mazza Edoardo
Published: March 2015

The structural and mechanical integrity of amnion is essential to prevent preterm premature rupture (PPROM) of the fetal membrane. In this study, the mechanical response of human amnion to repeated loading and the microstructural mechanisms determining its behavior were investigated. Inflation and uniaxial cyclic tests were combined with corresponding in situ experiments in a multiphoton microscope (MPM). Fresh unfixed amnion was imaged during loading and changes in thickness and collagen orientation were quantified. Mechanical and in situ experiments revealed differences between the investigated configurations in the deformation and microstructural mechanisms. Repeated inflation induces a significant but reversible volume change and is characterized by high energy dissipation. Under uniaxial tension, volume reduction is associated with low energy, unrecoverable in-plane fiber reorientation.
Application of V-Belt Continuously Variable Transmission System Using Hybrid Recurrent Laguerre Orthogonal Polynomials Neural Network Control System and Modified Particle Swarm Optimization
Authors: Lin Chih-Hong
Published: March 2015

Because the V-belt continuously variable transmission (CVT) system spurred by permanent magnet synchronous motor (PMSM) has unknown nonlinear and time-varying properties, the better control performance design for the linear control design is a time consuming procedure. In order to conquer difficulties for design of the linear controllers, the hybrid recurrent Laguerre orthogonal polynomials neural network (NN) control system, which has online learning ability to react to unknown nonlinear and time-varying characteristics, is developed for controlling PMSM servo-driven V-belt CVT system with the lumped nonlinear load disturbances. The hybrid recurrent Laguerre orthogonal polynomials NN control system consists of an inspector control, a recurrent Laguerre orthogonal polynomials NN control with adaptation law, and a recouped control with estimation law. Moreover, the adaptation law of online parameters in the recurrent Laguerre orthogonal polynomials NN is originated from Lyapunov stability theorem. Additionally, two varied learning rates of the parameters by means of modified particle swarm optimization (PSO) are posed in order to achieve better convergence. At last, comparative studies shown by experimental results are illustrated in order to verify the effectiveness of the proposed control scheme.
Low temperature plasma enhanced atomic layer deposition of conducting zirconium nitride films using tetrakis (dimethylamido) zirconium and forming gas (5% H2 + 95% N2) plasma
Authors: Muneshwar Triratna , Cadien Ken
Published: March 2015

Zirconium nitride (ZrN) has the lowest bulk electrical resistivity and high thermal stability among group IV and V transition metal nitrides, which makes it a promising material for ULSI applications such as a diffusion barrier for Cu interconnects, contact metal in III-V semiconductor devices, and in high density memory structures. Plasma enhanced atomic layer deposition (PEALD) of conducting ZrN thin films using Zr[N(CH3)2]4 and forming gas (5% H2 + 95% N2) plasma is reported in this article. The growth per cycle (GPC) for every deposition was determined from analysis of dynamic in-situ spectroscopic ellipsometry (d-iSE) measurements. An experimental design is proposed for faster determination of ALD growth saturation curves. At substrate temperature of 150 °C, a GPC of 0.10 nm/cycle was observed for self-limiting ZrN PEALD growth. The electrical resistivity of ZrN films deposited on SiO2 substrate was found to be 559.5 ± 18.5 μΩ cm with negligible change in resistivity even after ∼1000 h exposure to air. The metallic behavior of our ZrN films was evident from the free electron dispersion component in dielectric response, the broad band of photoelectron emission across Fermi level and the positive temperature coefficient for resistivity of 0.0088/ °C.
Comparison of film measurements and Monte Carlo simulations of dose delivered with very high‐energy electron beams in a polystyrene phantom
Authors: Bazalova‐Carter Magdalena , Liu Michael , Palma Bianey , Dunning Michael , McCormick Doug , Hemsing Erik , Nelson Janice , Jobe Keith , Colby Eric , Koong Albert C. , Tantawi Sami , Dolgashev Valery , Maxim Peter G. , Loo Billy W.
Published: March 2015

Purpose:

To measure radiation dose in a water‐equivalent medium from very high‐energy electron (VHEE) beams and make comparisons to Monte Carlo (MC) simulation results.

Methods:

Dose in a polystyrene phantom delivered by an experimental VHEE beam line was measured with Gafchromic films for three 50 MeV and two 70 MeV Gaussian beams of 4.0–6.9 mm FWHM and compared to corresponding MC‐simulated dose distributions. MC dose in the polystyrene phantom was calculated with the EGSnrc/BEAMnrc and DOSXYZnrc codes based on the experimental setup. Additionally, the effect of 2% beam energy measurement uncertainty and possible non‐zero beam angular spread on MC dose distributions was evaluated.

Results:

MC simulated percentage depth dose (PDD) curves agreed with measurements within 4% for all beam sizes at both 50 and 70 MeV VHEE beams. Central axis PDD at 8 cm depth ranged from 14% to 19% for the 5.4–6.9 mm 50 MeV beams and it ranged from 14% to 18% for the 4.0–4.5 mm 70 MeV beams. MC simulated relative beam profiles of regularly shaped Gaussian beams evaluated at depths of 0.64 to 7.46 cm agreed with measurements to within 5%. A 2% beam energy uncertainty and 0.286° beam angular spread corresponded to a maximum 3.0% and 3.8% difference in depth dose curves of the 50 and 70 MeV electron beams, respectively. Absolute dose differences between MC simulations and film measurements of regularly shaped Gaussian beams were between 10% and 42%.

Conclusions:

The authors demonstrate that relative dose distributions for VHEE beams of 50–70 MeV can be measured with Gafchromic films and modeled with Monte Carlo simulations to an accuracy of 5%. The reported absolute dose differences likely caused by imperfect beam steering and subsequent charge loss revealed the importance of accurate VHEE beam control and diagnostics.
Development of a phantom to validate high‐dose‐rate brachytherapy treatment planning systems with heterogeneous algorithms
Authors: Moura Eduardo S. , Micka John A. , Hammer Cliff G. , Culberson Wesley S. , DeWerd Larry A. , Rostelato Maria Elisa C. M. , Zeituni Carlos A.
Published: March 2015

Purpose:

This work presents the development of a phantom to verify the treatment planning system (TPS) algorithms used for high‐dose‐rate (HDR) brachytherapy. It is designed to measure the relative dose in a heterogeneous media. The experimental details used, simulation methods, and comparisons with a commercial TPS are also provided.

Methods:

To simulate heterogeneous conditions, four materials were used: Virtual Water™ (VM), BR50/50™, cork, and aluminum. The materials were arranged in 11 heterogeneity configurations. Three dosimeters were used to measure the relative response from a HDR 192Ir source: TLD‐100™, Gafchromic® EBT3 film, and an Exradin™ A1SL ionization chamber. To compare the results from the experimental measurements, the various configurations were modeled in the penelope/penEasy Monte Carlo code. Images of each setup geometry were acquired from a CT scanner and imported into BrachyVision™ TPS software, which includes a grid‐based Boltzmann solver Acuros™. The results of the measurements performed in the heterogeneous setups were normalized to the dose values measured in the homogeneous Virtual Water™ setup and the respective differences due to the heterogeneities were considered. Additionally, dose values calculated based on the American Association of Physicists in Medicine‐Task Group 43 formalism were compared to dose values calculated with the Acuros™ algorithm in the phantom. Calculated doses were compared at the same points, where measurements have been performed.

Results:

Differences in the relative response as high as 11.5% were found from the homogeneous setup when the heterogeneous materials were inserted into the experimental phantom. The aluminum and cork materials produced larger differences than the plastic materials, with the BR50/50™ material producing results similar to the Virtual Water™ results. Our experimental methods agree with the penelope/penEasy simulations for most setups and dosimeters. The TPS relative differences with the Acuros™ algorithm were similar in both experimental and simulated setups. The discrepancy between the BrachyVision™, Acuros™, and TG‐43 dose responses in the phantom described by this work exceeded 12% for certain setups.

Conclusions:

The results derived from the phantom measurements show good agreement with the simulations and TPS calculations, using Acuros™ algorithm. Differences in the dose responses were evident in the experimental results when heterogeneous materials were introduced. These measurements prove the usefulness of the heterogeneous phantom for verification of HDR treatment planning systems based on model‐based dose calculation algorithms.
Phoneme restoration and empirical coverage of interactive activation and adaptive resonance models of human speech processing
Authors: Magnuson James S.
Published: March 2015

Grossberg and Kazerounian [(2011). J. Acoust. Soc. Am. 130, 440–460] present a model of sequence representation for spoken word recognition, the cARTWORD model, which simulates essential aspects of phoneme restoration. Grossberg and Kazerounian also include simulations with the TRACE model presented by McClelland and Elman [(1986). Cognit. Psychol. 18, 1–86] that seem to indicate that TRACE cannot simulate phoneme restoration. Grossberg and Kazerounian also claim cARTWORD should be preferred to TRACE because of TRACE's implausible approach to sequence representation (reduplication of time-specific units) and use of non-modulatory feedback (i.e., without position-specific bottom-up support). This paper responds to Grossberg and Kazerounian first with TRACE simulations that account for phoneme restoration when appropriately constructed noise is used (and with minor changes to TRACE phoneme definitions), then reviews the case for reduplicated units and feedback as implemented in TRACE, as well as TRACE's broad and deep coverage of empirical data. Finally, it is argued that cARTWORD is not comparable to TRACE because cARTWORD cannot represent sequences with repeated elements, has only been implemented with small phoneme and lexical inventories, and has been applied to only one phenomenon (phoneme restoration). Without evidence that cARTWORD captures a similar range and detail of human spoken language processing as alternative models, it is premature to prefer cARTWORD to TRACE.
Three speech sounds, one motor action: Evidence for speech-motor disparity from English flap production
Authors: Derrick Donald , Stavness Ian , Gick Bryan
Published: March 2015

The assumption that units of speech production bear a one-to-one relationship to speech motor actions pervades otherwise widely varying theories of speech motor behavior. This speech production and simulation study demonstrates that commonly occurring flap sequences may violate this assumption. In the word “Saturday,” a sequence of three sounds may be produced using a single, cyclic motor action. Under this view, the initial upward tongue tip motion, starting with the first vowel and moving to contact the hard palate on the way to a retroflex position, is under active muscular control, while the downward movement of the tongue tip, including the second contact with the hard palate, results from gravity and elasticity during tongue muscle relaxation. This sequence is reproduced using a three-dimensional computer simulation of human vocal tract biomechanics and differs greatly from other observed sequences for the same word, which employ multiple targeted speech motor actions. This outcome suggests that a goal of a speaker is to produce an entire sequence in a biomechanically efficient way at the expense of maintaining parity within the individual parts of the sequence.
Experimental investigation of the accuracy of a vibroacoustic model for sandwich-composite panels
Authors: Cherif Raef , Atalla Noureddine
Published: March 2015

This paper presents a detailed experimental validation of a general laminate model to predict the vibroacoustic behavior of flat sandwich-composite panels. The accuracy of the model is investigated using a thin and a thick sandwich panel over a large frequency band. Several indicators are compared including the structural wavenumber, modal density, damping loss factor, radiation efficiency, and sound transmission loss. The accuracy of a simpler model based on identifying effective properties of an equivalent orthotropic panel from the General Laminate Model is also discussed. Results show that the vibroacoustic behaviors of flat sandwich-composite panels are accurately estimated using the used model and compare well to the equivalent panel model (for total transmission loss). This experimental investigation is generic and can be used as a benchmark to validate other sandwich models.
Exploring the source of the mid-level hump for intensity discrimination in quiet and the effects of noise
Authors: Roverud Elin , Strickland Elizabeth A.
Published: March 2015

Intensity discrimination Weber fractions (WFs) measured for short, high-frequency tones in quiet are larger at mid levels than at lower or higher levels. The source of this “mid-level hump” is a matter of debate. One theory is that the mid-level hump reflects basilar-membrane compression, and that WFs decrease at higher levels due to spread-of-excitation cues. To test this theory, Experiment 1 measured the mid-level hump and growth-of-masking functions to estimate the basilar membrane input/output (I/O) function in the same listeners. Results showed the initial rise in WFs could be accounted for by the change in I/O function slope, but there was additional unexplained variability in WFs. Previously, Plack [(1998). J. Acoust. Soc. Am. 103(5), 2530–2538] showed that long-duration notched noise (NN) presented with the tone reduced the mid-level hump even with a temporal gap in the NN. Plack concluded the results were consistent with central profile analysis. However, simultaneous, forward, and backward NN were not examined separately, which may independently test peripheral and central mechanisms of the NN. Experiment 2 measured WFs at the mid-level hump in the presence of NN and narrowband noise of different durations and temporal positions relative to the tone. Results varied across subjects, but were consistent with more peripheral mechanisms.
Using speech sounds to test functional spectral resolution in listeners with cochlear implants
Authors: Winn Matthew B. , Litovsky Ruth Y.
Published: March 2015

In this study, spectral properties of speech sounds were used to test functional spectral resolution in people who use cochlear implants (CIs). Specifically, perception of the /ba/-/da/ contrast was tested using two spectral cues: Formant transitions (a fine-resolution cue) and spectral tilt (a coarse-resolution cue). Higher weighting of the formant cues was used as an index of better spectral cue perception. Participants included 19 CI listeners and 10 listeners with normal hearing (NH), for whom spectral resolution was explicitly controlled using a noise vocoder with variable carrier filter widths to simulate electrical current spread. Perceptual weighting of the two cues was modeled with mixed-effects logistic regression, and was found to systematically vary with spectral resolution. The use of formant cues was greatest for NH listeners for unprocessed speech, and declined in the two vocoded conditions. Compared to NH listeners, CI listeners relied less on formant transitions, and more on spectral tilt. Cue-weighting results showed moderately good correspondence with word recognition scores. The current approach to testing functional spectral resolution uses auditory cues that are known to be important for speech categorization, and can thus potentially serve as the basis upon which CI processing strategies and innovations are tested.
Eigenbeam analysis of the diversity in bat biosonar beampatterns
Authors: Caspers Philip , Müller Rolf
Published: March 2015

A quantitative analysis of the interspecific variability in bat biosonar beampatterns has been carried out on 267 numerical predictions of emission and reception beampatterns from 98 different species. Since these beampatterns did not share a common orientation, an alignment was necessary to analyze the variability in the shape of the patterns. To achieve this, beampatterns were aligned using a pairwise optimization framework based on a rotation-dependent cost function. The sum of the p-norms between beam-gain functions across frequency served as a figure of merit. For a representative subset of the data, it was found that all pairwise beampattern alignments resulted in a unique global minimum. This minimum was found to be contained in a subset of all possible beampattern rotations that could be predicted by the overall beam orientation. Following alignment, the beampatterns were decomposed into principal components. The average beampattern consisted of a symmetric, positionally static single lobe that narrows and became progressively asymmetric with increasing frequency. The first three “eigenbeams” controlled the beam width of the beampattern across frequency while higher rank eigenbeams account for symmetry and lobe motion. Reception and emission beampatterns could be distinguished (85% correct classification) based on the first 14 eigenbeams.
Effect of musical experience on learning lexical tone categories
Authors: Zhao T. Christina , Kuhl Patricia K.
Published: March 2015

Previous studies suggest that musicians show an advantage in processing and encoding foreign-language lexical tones. The current experiments examined whether musical experience influences the perceptual learning of lexical tone categories. Experiment I examined whether musicians with no prior experience of tonal languages differed from nonmusicians in the perception of a lexical tone continuum. Experiment II examined whether short-term perceptual training on lexical tones altered the perception of the lexical tone continuum differentially in English-speaking musicians and nonmusicians. Results suggested that (a) musicians exhibited higher sensitivity overall to tonal changes, but perceived the lexical tone continuum in a manner similar to nonmusicians (continuously), in contrast to native Mandarin speakers (categorically); and (b) short-term perceptual training altered perception; however, there were no significant differences between the effects of training on musicians and nonmusicians.
A multistage minimum variance distortionless response beamformer for noise reduction
Authors: Pan Chao , Chen Jingdong , Benesty Jacob
Published: March 2015

This paper develops a multistage approach to the implementation of the minimum variance distortionless response (MVDR) beamformer. It first divides the microphone array of M sensors into M/2 subarrays with each subarray having only two microphones, and a two-channel MVDR beamformer is performed with each subarray. The M/2 subarrays' outputs are then treated as the inputs of M/4 subarrays of two channels in the next stage. Similarly, a two-channel MVDR beamformer is performed with each subarray in the second stage. This process is repeated till the last stage that has only a single output. This multistage MVDR beamformer has the following properties: (1) Its performance is identical to that of the conventional MVDR beamformer in spatially uncorrelated noise; (2) it is much more robust than the conventional MVDR beamformer in diffuse noise, i.e., it has a significantly higher white noise gain as compared to the traditional MVDR beamformer; and (3) its complexity is an order of magnitude smaller than that of the traditional MVDR beamformer. This basic principle can also be easily generalized to the case where every subarray has more than two microphones.
Timelapse ultrasonic tomography for measuring damage localization in geomechanics laboratory tests
Authors: Tudisco Erika , Roux Philippe , Hall Stephen A. , Viggiani Giulia M. B. , Viggiani Gioacchino
Published: March 2015

Variation of mechanical properties in materials can be detected non-destructively using ultrasonic measurements. In particular, changes in elastic wave velocity can occur due to damage, i.e., micro-cracking and particles debonding. Here the challenge of characterizing damage in geomaterials, i.e., rocks and soils, is addressed. Geomaterials are naturally heterogeneous media in which the deformation can localize, so that few measurements of acoustic velocity across the sample are not sufficient to capture the heterogeneities. Therefore, an ultrasonic tomography procedure has been implemented to map the spatial and temporal variations in propagation velocity, which provides information on the damage process. Moreover, double beamforming has been successfully applied to identify and isolate multiple arrivals that are caused by strong heterogeneities (natural or induced by the deformation process). The applicability of the developed experimental technique to laboratory geomechanics testing is illustrated using data acquired on a sample of natural rock before and after being deformed under triaxial compression. The approach is then validated and extended to time-lapse monitoring using data acquired during plane strain compression of a sample including a well defined layer with different mechanical properties than the matrix.
Visual speech information: A help or hindrance in perceptual processing of dysarthric speech
Authors: Borrie Stephanie A.
Published: March 2015

This study investigated the influence of visual speech information on perceptual processing of neurologically degraded speech. Fifty listeners identified spastic dysarthric speech under both audio (A) and audiovisual (AV) conditions. Condition comparisons revealed that the addition of visual speech information enhanced processing of the neurologically degraded input in terms of (a) acuity (percent phonemes correct) of vowels and consonants and (b) recognition (percent words correct) of predictive and nonpredictive phrases. Listeners exploited stress-based segmentation strategies more readily in AV conditions, suggesting that the perceptual benefit associated with adding visual speech information to the auditory signal—the AV advantage—has both segmental and suprasegmental origins. Results also revealed that the magnitude of the AV advantage can be predicted, to some degree, by the extent to which an individual utilizes syllabic stress cues to inform word recognition in AV conditions. Findings inform the development of a listener-specific model of speech perception that applies to processing of dysarthric speech in everyday communication contexts.
Influence of wall scattering on the early fine structures of measured room impulse responses
Authors: Jeon Jin Yong , Jang Hyung Suk , Kim Yong Hee , Vorländer Michael
Published: March 2015

The effects of wall diffusing elements on sound-field diffuseness were investigated in a tenth-scale model hall and in a real recital hall. Acoustical measurements were carried out in both halls to measure the surface diffusivity of the lateral walls. In the scale model, the surfaces of the lateral walls and the soffits were covered with diffusers; in the recital hall, the front halves of both lateral walls were treated using reflective panels and absorptive materials. Objective characteristics were investigated using conventional room acoustic parameters and the number of peaks (Np) computed for the measured impulse responses, which were recorded under diffusive, reflective, and absorptive conditions. In addition, as a measure of the diffuse sound fields, the relative standard deviations (RSDs) of the acoustical parameters were investigated. The diffusive surfaces caused a decrease in the standard deviation of the early decay time and an increase in the Np at higher frequency bands. Auditory experiments using a paired comparison method revealed that the perception of subjective diffuseness could be quantified by using Np. In addition, one listener group's preference was correlated with Np and varied depending on different wall surface treatments.
The Biomechanical Determinants of Concussion: Finite Element Simulations to Investigate Tissue-Level Predictors of Injury During Sporting Impacts to the Unprotected Head
Authors: Patton Declan A. , McIntosh Andrew S. , Kleiven Svein
Published: March 2015

Biomechanical studies of concussions have progressed from qualitative observations of head impacts to physical and numerical reconstructions, direct impact measurements, and finite element analyses. Supplementary to a previous study, which investigated maximum principal strain, the current study used a detailed finite element head model to simulate unhelmeted concussion and no-injury head impacts and evaluate the effectiveness of various tissue-level brain injury predictors: strain rate, product of strain and strain rate, cumulative strain damage measure, von Mises stress, and intracranial pressure. Von Mises stress was found to be the most effective predictor of concussion. It was also found that the thalamus and corpus callosum were brain regions with strong associations with concussion. Tentative tolerance limits for tissue-level predictors were proposed in an attempt to broaden the understanding of unhelmeted concussions. For the thalamus, tolerance limits were proposed for a 50% likelihood of concussion: 2.24 kPa, 24.0 s−1, and 2.49 s−1 for von Mises stress, strain rate, and the product of strain and strain rate, respectively. For the corpus callosum, tolerance limits were proposed for a 50% likelihood of concussion: 3.51 kPa, 25.1 s−1, and 2.76 s−1 for von Mises stress, strain rate, and the product of strain and strain rate, respectively.
Ceftriaxone-Resistant Salmonella enterica Serotype Typhimurium Sequence Type 313 from Kenyan Patients Is Associated with the
bla
CTX-M-15
Gene on a Novel IncHI2 Plasmid
Authors: Kariuki Samuel , Okoro Chinyere , Kiiru John , Njoroge Samuel , Omuse Geoffrey , Langridge Gemma , Kingsley Robert A. , Dougan Gordon , Revathi Gunturu
Published: March 2015

Multidrug-resistant bacteria pose a major challenge to the clinical management of infections in resource-poor settings. Although nontyphoidal
Salmonella
(NTS) bacteria cause predominantly enteric self-limiting illness in developed countries, NTS is responsible for a huge burden of life-threatening bloodstream infections in sub-Saharan Africa. Here, we characterized nine
S
. Typhimurium isolates from an outbreak involving patients who initially failed to respond to ceftriaxone treatment at a referral hospital in Kenya. These
Salmonella enterica
serotype Typhimurium isolates were resistant to ampicillin, chloramphenicol, cefuroxime, ceftriaxone, aztreonam, cefepime, sulfamethoxazole-trimethoprim, and cefpodoxime. Resistance to β-lactams, including to ceftriaxone, was associated with carriage of a combination of
bla
CTX-M-15
,
bla
OXA-1
, and
bla
TEM-1
genes. The genes encoding resistance to heavy-metal ions were borne on the novel IncHI2 plasmid pKST313, which also carried a pair of class 1 integrons. All nine isolates formed a single clade within
S
. Typhimurium ST313, the major clone of an ongoing invasive NTS epidemic in the region. This emerging ceftriaxone-resistant clone may pose a major challenge in the management of invasive NTS in sub-Saharan Africa.
Artemisinin-Resistant Plasmodium falciparum Parasites Exhibit Altered Patterns of Development in Infected Erythrocytes
Authors: Hott Amanda , Casandra Debora , Sparks Kansas N. , Morton Lindsay C. , Castanares Geocel-Grace , Rutter Amanda , Kyle Dennis E.
Published: March 2015

Artemisinin derivatives are used in combination with other antimalarial drugs for treatment of multidrug-resistant malaria worldwide. Clinical resistance to artemisinin recently emerged in southeast Asia, yet
in vitro
phenotypes for discerning mechanism(s) of resistance remain elusive. Here, we describe novel phenotypic resistance traits expressed by artemisinin-resistant
Plasmodium falciparum
. The resistant parasites exhibit altered patterns of development that result in reduced exposure to drug at the most susceptible stage of development in erythrocytes (trophozoites) and increased exposure in the most resistant stage (rings). In addition, a novel
in vitro
delayed clearance assay (DCA) that assesses drug effects on asexual stages was found to correlate with parasite clearance half-life
in vivo
as well as with mutations in the Kelch domain gene associated with resistance (Pf3D7_1343700). Importantly, all of the resistance phenotypes were stable in cloned parasites for more than 2 years without drug pressure. The results demonstrate artemisinin-resistant
P. falciparum
has evolved a novel mechanism of phenotypic resistance to artemisinin drugs linked to abnormal cell cycle regulation. These results offer insights into a novel mechanism of drug resistance in
P. falciparum
and new tools for monitoring the spread of artemisinin resistance.
Subtype-Specific Analysis of the K65R Substitution in HIV-1 That Confers Hypersusceptibility to a Novel Nucleotide-Competing Reverse Transcriptase Inhibitor
Authors: Xu Hong-Tao , Colby-Germinario Susan P. , Quashie Peter K. , Bethell Richard , Wainberg Mark A.
Published: March 2015

Compound A is a novel nucleotide-competing HIV-1 reverse transcriptase (RT) inhibitor (NcRTI) that selects for a unique W153L substitution that confers hypersusceptibility to tenofovir, while the K65R substitution in RT confers resistance against tenofovir and enhances susceptibility to NcRTIs. Although the K65R substitution is more common in subtype C viruses, the impact of subtype variability on NcRTI susceptibility has not been studied. In the present study, we performed experiments with compound A by using purified recombinant RT enzymes and viruses of subtypes B and C and circulating recombinant form CRF_A/G. We confirmed the hypersusceptibility of K65R substitution-containing RTs to compound A for subtype C, CRF_A/G, and subtype B. Steady-state kinetic analysis showed that K65R RTs enhanced the susceptibility to compound A by increasing binding of the inhibitor to the nucleotide binding site of RT in a subtype-independent manner, without significantly discriminating against the natural nucleotide substrate. These data highlight the potential utility of NcRTIs, such as compound A, for treatment of infections with K65R substitution-containing viruses, regardless of HIV-1 subtype.
Predominance of KPC-3 in a Survey for Carbapenemase-Producing Enterobacteriaceae in Portugal
Authors: Manageiro Vera , Ferreira Eugénia , Almeida Joana , Barbosa Stephanie , Simões Constança ,   Antibiotic Resistance Surveillance Program in Portugal (ARSIP), Bonomo Robert A. , Caniça Manuela
Published: March 2015

Among the 2,105
Enterobacteriaceae
tested in a survey done in Portugal, 165 were nonsusceptible to carbapenems, from which 35 (26
Klebsiella pneumoniae
, 3
Escherichia coli
, 2
Enterobacter aerogenes
, and 3
Enterobacter cloacae
isolates and 1
Klebsiella oxytoca
isolate) were confirmed to be carbapenemase producers by the presence of 30
Tn
4401d-
bla
KPC-3
, 4
intI
3-
bla
GES-5
, and one
intI
1-
bla
VIM-2
gene, alone or in combination with other
bla
genes. The dissemination of
bla
KPC-3
gene carried by an IncF plasmid suggests lateral gene transfer as a major mechanism of dissemination.
Characterization of CPAF Critical Residues and Secretion during Chlamydia trachomatis Infection
Authors: Yang Zhangsheng , Tang Lingli , Sun Xin , Chai Jijie , Zhong Guangming
Published: March 2015

CPAF (chlamydial protease-like activity factor), a
Chlamydia
serine protease, is activated via proximity-induced intermolecular dimerization that triggers processing and removal of an inhibitory peptide occupying the CPAF substrate-binding groove. An active CPAF is a homodimer of two identical intramolecular heterodimers, each consisting of 29-kDa N-terminal and 35-kDa C-terminal fragments. However, critical residues for CPAF intermolecular dimerization, catalytic activity, and processing were defined in cell-free systems. Complementation of a CPAF-deficient chlamydial organism with a plasmid-encoded CPAF has enabled us to characterize CPAF during infection. The transformants expressing CPAF mutated at intermolecular dimerization, catalytic, or cleavage residues still produced active CPAF, although at a lower efficiency, indicating that CPAF can tolerate more mutations inside
Chlamydia
-infected cells than in cell-free systems. Only by simultaneously mutating both intermolecular dimerization and catalytic residues was CPAF activation completely blocked during infection, both indicating the importance of the critical residues identified in the cell-free systems and exploring the limit of CPAF's tolerance for mutations in the intracellular environment. We further found that active CPAF was always detected in the host cell cytoplasm while nonactive CPAF was restricted to within the chlamydial inclusions, regardless of how the infected cell samples were treated. Thus, CPAF translocation into the host cell cytoplasm correlates with CPAF enzymatic activity and is not altered by sample treatment conditions. These observations have provided new evidence for CPAF activation and translocation, which should encourage continued investigation of CPAF in chlamydial pathogenesis.
Colony Morphology Variation of Burkholderia pseudomallei Is Associated with Antigenic Variation and O-Polysaccharide Modification
Authors: Wikraiphat Chanthiwa , Saiprom Natnaree , Tandhavanant Sarunporn , Heiss Christian , Azadi Parastoo , Wongsuvan Gumphol , Tuanyok Apichai , Holden Matthew T. G. , Burtnick Mary N. , Brett Paul J. , Peacock Sharon J. , Chantratita Narisara
Published: March 2015

Burkholderia pseudomallei
is a CDC tier 1 select agent that causes melioidosis, a severe disease in humans and animals. Persistent infections are common, and there is currently no vaccine available. Lipopolysaccharide (LPS) is a potential vaccine candidate.
B. pseudomallei
expresses three serologically distinct LPS types. The predominant O-polysaccharide (OPS) is an unbranched heteropolymer with repeating
d
-glucose and 6-deoxy-
l
-talose residues in which the 6-deoxy-
l
-talose residues are variably replaced with
O
-acetyl and
O
-methyl modifications. We observed that primary clinical
B. pseudomallei
isolates with mucoid and nonmucoid colony morphologies from the same sample expressed different antigenic types distinguishable using an LPS-specific monoclonal antibody (MAb). MAb-reactive (nonmucoid) and nonreactive (mucoid) strains from the same patient exhibited identical LPS banding patterns by silver staining and indistinguishable genotypes. We hypothesized that LPS antigenic variation reflected modification of the OPS moieties. Mutagenesis of three genes involved in LPS synthesis was performed in
B. pseudomallei
K96243. Loss of MAb reactivity was observed in both
wbiA
(encoding a 2-
O
-acetyltransferase) and
wbiD
(putative methyl transferase) mutants. The structural characteristics of the OPS moieties from isogenic nonmucoid strain 4095a and mucoid strain 4095c were further investigated. Utilizing nuclear magnetic resonance (NMR) spectroscopy, we found that
B. pseudomallei
4095a and 4095c OPS antigens exhibited substitution patterns that differed from the prototypic OPS structure. Specifically, 4095a lacked 4-
O
-acetylation, while 4095c lacked both 4-
O
-acetylation and 2-
O
-methylation. Our studies indicate that
B. pseudomallei
OPS undergoes antigenic variation and suggest that the 9D5 MAb recognizes a conformational epitope that is influenced by both
O
-acetyl and
O
-methyl substitution patterns.