bluuebunny/crossref_metadata_2025 huggingface dataset:
Fine‐needle aspiration cytology as the first pathological diagnostic modality in breast lesions: A comparison with core needle biopsy
Authors: Park Sang‐Mo , Lee Dong‐Wha , Jin So‐Young , Kim Dong‐Won , Jeen Yoon‐Mi , Choi In‐Ho
Published: February 2010

Background and aim: Breast cancer is the second most common malignancy in Korean women. Fine needle aspiration cytology (FNAC) has been used as the first‐line pathological modality; however, use of core needle biopsy (CNB) is on the increase. FNAC is a cost effective, less invasive and rapid method for evaluation of breast lesions. The limitations of FNAC, such as high false negative rates and equivocal results restrict its use. The aim of this study is to evaluate FNAC as a diagnostic tool in comparison with CNB by matching corresponding excision specimens. Methods: From May, 2003 to April, 2008, 753 cases of FNAC, 331 cases of CNB, and 98 cases of combined FNAC and CNB were collected. Diagnoses with FNAC and CNB were compared with excision. Results: Sensitivity, specificity, and diagnostic accuracy of FNAC were 93.8%, 80.8%, and 90.1%, respectively. Those of CNB were 92.1%, 90.9%, and 92.3%, and combined FNAC and CNB, 100%, 77.8%, and 98.0%. There were no false positive cases in either the FNAC or the CNB group. False negative rates were 6.2% in FNAC and 9.9% in CNB. Sampling error was the cause of error or a false negative result in all FNAC samples, and all but one CNB sample. Diagnostic accuracy of FNAC was superior to that of CNB for lesions between 1 cm and 2 cm. Conclusions: Our data suggest that FNAC is an accurate and reliable first line diagnostic tool for evaluation of breast lesions when compared with core biopsy.
Prognostic significance of pSTAT3 and Survivin expression in diffuse large B‐cell lymphoma
Authors: Sung Ji‐Youn , Lim Sung‐Jig , Kim Youn Wha , Lee Juhie
Published: February 2010

Background and aim: The activated phosphorylated form of signal transducer and activator of transcription 3 (pSTAT3) up‐regulates multiple downstream targets, including Survivin, which is an inhibitor of apoptosis, and has been implicated as an important process in malignant progression. The purpose of this study was to investigate the expression of pSTAT3 and Survivin in diffuse large B cell lymphomas (DLBCL) for their clinicopathological significance. Methods: Using tissue microarrays constructed from 102 DLBCLs, immunohistochemistry was done for pSTAT3 and Survivin. Results: Immunoreactivity for pSTAT3 and Survivin was seen in 41% and 46% of 102 patients of DLBCL. Patients who expressed pSTAT3 were more likely to have Survivin (p < 0.001) and p53 expressions (p= 0.002). According to the sub‐groups of DLBCL, non‐germinal center B cell (non‐GCB) group was more likely to express pSTAT3 and Survivin. Both the pSTAT3 and Survivin expression were significantly associated with short overall survival by Kaplan–Meier survival curves and log‐rank tests in both overall (p= 0.021 and p= 0.002) and non‐GCB group of DLBCL (p= 0.023 and p= 0.006). Multivariate analysis confirmed that Survivin was an independent prognostic factor in both overall DLBCL (p= 0.014) and non‐GCB group (p= 0.032). Conclusions: pSTAT3 and Survivin expression appear to be important prognostic factors for DLBCL patients.
Primary retroperitoneal meningioma: A case report
Authors: Lee So Young , Kim Ji Hun , Kim Mi Jung , Cho Kyung Ja , You Eun Sil , Khang Shin Kwang
Published: February 2010

Primary extracranial meningiomas are rare disease entities, occurring primarily in the head and neck. We herein present a very rare case of primary extracranial meningioma of the retroperitoneum, observed in a 56‐year‐old man who presented with a retroperitoneal mass measuring 11 cm in its greatest dimension. Histological examination revealed sheets of spindle cells with frequent whorling patterns. The neoplastic cells had abundant light eosinophilic cytoplasm with minimal mitosis or cellular atypism. Immunohistochemical analysis demonstrated diffuse and strong positivity for vimentin and epithelial membrane antigen. Ultrastructural findings revealed abundant intermediate filaments, complex interdigitating cellular processes, and desmosome‐like intercellular junctions, all of which are characteristic ultrastructural features of meningiomas. The patient was free of recurrence or metastasis 11 months after surgery. To the best of our knowledge, this is only the second reported case of primary retroperitoneal meningioma.
Surface-charging effect of capacitively coupled plasmas driven by combined dc/rf sources
Authors: Zhang Quan-Zhi , Jiang Wei , Zhao Shu-Xia , Wang You-Nian
Published: February 2010

The surface charging effect in hybrid dc/rf capacitively coupled plasmas is investigated by particle-in-cell/Monte Carlo simulations with an equivalent-circuit module. When the thickness of the dielectric is fixed, the self-bias dc voltage induced by the charge accumulated in the dielectric first increases and then decreases with increased dc voltage. The ratio of electron-to-ion charge flowing into the dielectric increases from −1.195 to −2.582. Increasing the dc voltage results in the number of high-energy ions bombarding the dielectric decreasing. The average electron energy at the dielectric decreases to the minimum value at the biggest self-bias dc voltage in the beginning and then rapidly increases. While fixing the dc source with thickening the dielectric, the self-bias dc voltage rises, but the charge ratio decreases. The average electron energy decreases monotonically and the ion-energy distributions (IEDs) at the dielectric are shifted toward the higher energy region. The results imply that the applied dc voltage may increase the electron flux and average energy to the dielectric at the cost of reduced etching rate, which may mitigate the notching effect. The applied dc voltage can also serve as a tool to modulate the ion IEDs. At the same time, a thicker dielectric will require higher applied dc voltage.
Prosodic peak estimation under segmental perturbations
Authors: Kochanski Greg
Published: February 2010

Despite the apparent simplicity, measuring the position of peaks in speech fundamental frequency (f0) can produce unexpected results in a model where f0 is the superposition of a supersegmental component and a segmental component. In these models, the measured f0 peak position can be as much as an entire syllable different from the peak of the intonation component. This difference can be large enough so that the measured peak positions could falsely suggest a phonological distinction in the intonation where none really exists. This paper then discusses measurement techniques that are less sensitive to segmental effects than directly measuring the position of the f0 maximum. A algorithm, called the “bracketed maximum,” is presented. The performance of these techniques is compared on a corpus of speech data where the intonation is expected to be in a stable position. The bracketed maximum can reduce the variance of peak position measurements by at least 15%, in the presence of changing segmental structure, thereby presumably yielding a more accurate measurement of the intonation peak position.
Polycrystalline gamma-plutonium’s elastic moduli versus temperature
Authors: Stroe I. , Betts J. B. , Trugman A. , Mielke C. H. , Mitchell J. N. , Ramos M. , Freibert F. J. , Ledbetter H. , Migliori A.
Published: February 2010

Resonant ultrasound spectroscopy was used to measure the elastic properties of pure polycrystalline P239u in the γ-phase. Shear and longitudinal elastic moduli were measured simultaneously and the bulk modulus was computed from them. A smooth, linear, and large decrease in all elastic moduli with increasing temperature was observed. The Poisson ratio was calculated and an increase from 0.242 at 519 K to 0.252 at 571 K was found. These measurements on extremely well-characterized pure Pu are in agreement with other reported results where overlap occurs. We calculated an approximate Debye temperature ΘD=144 K. Determined from the temperature variation in the bulk modulus, γ-Pu shows the same Grüneisen parameter as copper.
Efficient numerical modeling of traffic noise
Authors: Salomons Erik M. , Zhou Han , Lohman Walter J. A.
Published: February 2010

An optimized method is presented for the numerical evaluation of the sound field generated by an incoherent line source, which is commonly used to model road and rail traffic noise. Two different solutions for the numerical integration over the line source are distinguished, a point source solution and a line source solution. With proper segmentation of the line source, both solutions yield accurate results. Special attention is paid to receiver positions close to the (infinite) line through the (finite) line source. At these positions, conventional methods give numerical errors, which occur frequently in calculations of large-scale noise maps of cities, employing automatically generated geographical input data. The problems are avoided by using the optimized method presented here. The method is based on a combination of angular segmentation and linear segmentation of the line source and can be used to minimize the number of point-to-point calculations for noise mapping.
Prediction of the acoustical performance of enclosures using a hybrid statistical energy analysis: Image source model
Authors: Sgard Franck , Nelisse Hugues , Atalla Noureddine , Amedin Celse Kafui , Oddo Remy
Published: February 2010

Enclosures are commonly used to reduce the sound exposure of workers to the noise radiated by machinery. Some acoustic predictive tools ranging from simple analytical tools to sophisticated numerical deterministic models are available to estimate the enclosure acoustical performance. However, simple analytical models are usually valid in limited frequency ranges because of underlying assumptions whereas numerical models are commonly limited to low frequencies. This paper presents a general and simple model for predicting the acoustic performance of large free-standing enclosures which is capable of taking into account the complexity of the enclosure configuration and covering a large frequency range. It is based on the statistical energy analysis (SEA) framework. The sound field inside the enclosure is calculated using the method of image sources. Sound transmission across the various elements of the enclosure is considered in the SEA formalism. The model is evaluated by comparison with existing methods and experimental results. The effect of several parameters such as enclosure geometry, panel materials, presence of noise control treatments, location of the source inside the enclosure, and presence of an opening has been investigated. The comparisons between the model and the experimental results show a good agreement for most of the tested configurations.
A computer model of auditory efferent suppression: Implications for the recognition of speech in noise
Authors: Brown Guy J. , Ferry Robert T. , Meddis Ray
Published: February 2010

The neural mechanisms underlying the ability of human listeners to recognize speech in the presence of background noise are still imperfectly understood. However, there is mounting evidence that the medial olivocochlear system plays an important role, via efferents that exert a suppressive effect on the response of the basilar membrane. The current paper presents a computer modeling study that investigates the possible role of this activity on speech intelligibility in noise. A model of auditory efferent processing [Ferry, R. T., and Meddis, R. (2007). J. Acoust. Soc. Am. 122, 3519–3526] is used to provide acoustic features for a statistical automatic speech recognition system, thus allowing the effects of efferent activity on speech intelligibility to be quantified. Performance of the “basic” model (without efferent activity) on a connected digit recognition task is good when the speech is uncorrupted by noise but falls when noise is present. However, recognition performance is much improved when efferent activity is applied. Furthermore, optimal performance is obtained when the amount of efferent activity is proportional to the noise level. The results obtained are consistent with the suggestion that efferent suppression causes a “release from adaptation” in the auditory-nerve response to noisy speech, which enhances its intelligibility.
A residual-potential boundary for time-dependent, infinite-domain problems in computational acoustics
Authors: Geers Thomas L. , Sprague Michael A.
Published: February 2010

A theoretically exact computational boundary is introduced that is based on modal residual potentials for the spherical geometry. The boundary produces a set of first-order, uncoupled ordinary differential equations for nodal boundary responses, and a set of uncoupled time-stepping equations for modal boundary responses. The two sets are coupled through nodal-modal transformation based on the orthogonal surface functions for the spherical boundary. Numerical results generated with the boundary are presented for a step-wave-excited, elastic, spherical shell submerged in an infinite acoustic medium. Extension of the method to other separable geometries for partial differential equations defined in unbounded domains is mentioned.
Structure of phonon focusing patterns in tetragonal crystals
Authors: Wang Litian
Published: February 2010

A set of critical conditions for the characteristic caustic points in the phonon focusing patterns in tetragonal crystals is formulated. A caustic line segment in the focusing pattern is generally associated with either a fold or a cusp on the wave surface. Most of the caustic lines are symmetrical with respect to the principal symmetry plane and can be characterized by the caustic points at the centers of the caustic lines. These characteristic caustic points originated from inflection/parabolic points with zero in-plane/ex-plane curvature, respectively. By employing the Stroh formalism, the inflection/parabolic points on the slowness surface are studied in terms of the so-called zero-curvature transonic states. Since these transonic states are related to extraordinary degeneracies in the Stroh eigenvalue equation, the conditions for the degeneracies can be regarded as critical conditions for the characteristic caustic points. These conditions provide an overview of global structure of the phonon focusing patterns in tetragonal crystals. A set of caustic lines in vicinity of (001) plane is also investigated and exemplified.
A mathematical model of vowel identification by users of cochlear implants
Authors: Sagi Elad , Meyer Ted A. , Kaiser Adam R. , Teoh Su Wooi , Svirsky Mario A.
Published: February 2010

A simple mathematical model is presented that predicts vowel identification by cochlear implant users based on these listeners’ resolving power for the mean locations of first, second, and/or third formant energies along the implanted electrode array. This psychophysically based model provides hypotheses about the mechanism cochlear implant users employ to encode and process the input auditory signal to extract information relevant for identifying steady-state vowels. Using one free parameter, the model predicts most of the patterns of vowel confusions made by users of different cochlear implant devices and stimulation strategies, and who show widely different levels of speech perception (from near chance to near perfect). Furthermore, the model can predict results from the literature, such as Skinner, et al. [(1995). Ann. Otol. Rhinol. Laryngol. 104, 307–311] frequency mapping study, and the general trend in the vowel results of Zeng and Galvin’s [(1999). Ear Hear. 20, 60–74] studies of output electrical dynamic range reduction. The implementation of the model presented here is specific to vowel identification by cochlear implant users, but the framework of the model is more general. Computational models such as the one presented here can be useful for advancing knowledge about speech perception in hearing impaired populations, and for providing a guide for clinical research and clinical practice.
Psychophysical tuning curves and recognition of highpass and lowpass filtered speech for a person with an inverted V-shaped audiogram
Authors: Vinay  , Moore Brian C. J.
Published: February 2010

A single subject whose audiogram resembled an inverted V shape (good hearing at 4000 Hz, and poorer hearing at other frequencies) was tested. Results of the threshold-equalizing noise test suggested that a dead region (DR) in the cochlea was present at all test frequencies from 500 to 3000 Hz, but no DR was present at 4000 Hz. Psychophysical tuning curves (PTCs) obtained using signal frequencies of 2000, 3000, 4000, and 6000 Hz showed upward shifted tips for the lowest two signal frequencies, and a downward shifted tip for the highest frequency. The results of the PTCs suggested a functioning region extending from 3900 to 5100 Hz, with DRs outside that range. The identification of nonsense syllables, amplified according to the “Cambridge formula,” was measured as a function of lowpass or highpass filter cutoff frequency. The results suggested that useful speech information could only be extracted from a limited frequency range around 4000 Hz.
Nonlinear progressive waves in a slide trombone resonator
Authors: Rendón Pablo L. , Orduña-Bustamante Felipe , Narezo Daniela , Pérez-López Antonio , Sorrentini Jacques
Published: February 2010

The propagation of finite-amplitude waves inside a slide trombone is studied through direct pressure measurements corresponding to dynamic extremes. A two-microphone method is used to separate left-moving and right-moving waves inside the trombone, permitting the detection of nonlinear effects associated with progressive waves. It is found that a redistribution of energy across the spectrum toward the higher-frequencies occurs for large distances and high initial pressure levels. These results are consistent with the theory of weakly nonlinear acoustics and also with those reported in this same context by other authors, but which have been obtained mostly through examination of standing-waves.
Deconvolution of sparse underwater acoustic multipath channel with a large time-delay spread
Authors: Zeng Wen-Jun , Jiang Xue , Li Xi-Lin , Zhang Xian-Da
Published: February 2010

The deconvolution of multipath underwater acoustic channel with a large time-delay spread is investigated. The channel deconvolution involves estimating the multipath time-delays and attenuation factors from a noisy received signal consisting of multiple overlapped signals. Similar to conventional deconvolution methods, the proposed method estimates channel impulse response based on least-squares criterion. However, the proposed method harnesses the sparse structure of an underwater acoustic channel, and ℓ1-norm of the channel impulse response is adopted as the cost function to be minimized. In addition, the available a priori knowledge of support constraint and attenuation factor constraint are imposed and channel deconvolution problem is converted to a convex optimization problem. Instead of employing the existing standard algorithms, which require huge storage space and high computational complexity, a simple iterative algorithm for solving the optimization problem with fast convergence rate and low complexity is developed. The computational complexity of the proposed algorithm is O(N log2(N)) per iteration with N being the length of the received signal. Simulation results confirm that the proposed method provides better performance in terms of temporal resolution and robustness to noise compared with other extant multipath channel deconvolution techniques.
Interaural cross correlation in a sound field represented by spherical harmonics
Authors: Rafaely Boaz , Avni Amir
Published: February 2010

Spatial impression is an important acoustic quality of concert halls. An accepted objective measure for spatial impression is the interaural cross-correlation (IACC) coefficient. Recently, spherical microphone arrays have been studied for room acoustics analysis and music recordings. This study presents a theoretical formulation for the computation of IACC using spherical-harmonics representations of the sound field, as measured by spherical microphone arrays, and spherical-harmonics representation of head-related transfer functions (HRTFs), taken from HRTF databases. As spherical microphone arrays typically use a finite number of microphones, they may not be able to capture the complete spatial information in a sound field. Therefore, the effect of limited spherical-harmonics order on the accuracy of IACC approximation using the proposed method is studied using simulated and measured data. The method presented in this paper can be further used to study the effect of limited spatial information on the spatial perception of sound fields.
Compensations in response to real-time formant perturbations of different magnitudes
Authors: MacDonald Ewen N. , Goldberg Robyn , Munhall Kevin G.
Published: February 2010

Previous auditory perturbation studies have demonstrated that talkers spontaneously compensate for real-time formant-shifts by altering formant production in a manner opposite to the perturbation. Here, two experiments were conducted to examine the effect of amplitude of perturbation on the compensatory behavior for the vowel /ε/. In the first experiment, 20 male talkers received three step-changes in acoustic feedback: F1 was increased by 50, 100, and 200 Hz, while F2 was simultaneously decreased by 75, 125, and 250 Hz. In the second experiment, 21 male talkers received acoustic feedback in which the shifts in F1 and F2 were incremented by +4 and −5 Hz on each utterance to a maximum of +350 and −450 Hz, respectively. In both experiments, talkers altered production of F1 and F2 in a manner opposite to that of the formant-shift perturbation. Compensation was approximately 25%–30% of the perturbation magnitude for shifts in F1 and F2 up to 200 and 250 Hz, respectively. As larger shifts were applied, compensation reached a plateau and then decreased. The similarity of results across experiments suggests that the compensatory response is dependent on the perturbation magnitude but not on the rate at which the perturbation is introduced.
Acoustic microstreaming around a gas bubble
Authors: Doinikov Alexander A. , Bouakaz Ayache
Published: February 2010

The problem of acoustic microstreaming that develops around a gas bubble in an ultrasound field is considered. It is shown that the solutions obtained previously by Wu and Du [(1997). J. Acoust. Soc. Am. 101, 1899–1907], which are based on the assumption that viscous effects are essential only within a thin boundary layer while beyond the boundary layer the liquid can be considered to be inviscid, lead to a severe underestimation of the power of acoustic streaming. An improved theory is suggested that corrects the errors of the previous theory and extends its limits. The proposed theory treats the entire bulk of the liquid outside the bubble and the gas inside the bubble as viscous heat-conducting fluids. No restrictions are imposed on the size of the bubble relative to the viscous, thermal, and sound wavelengths in the ambient liquid and those in the internal gas medium. All modes of the bubble’s motion (volume pulsation, translation, and shape oscillations) are taken into account. Expressions for the radial and tangential stresses produced by the acoustic streaming are also derived. Numerical examples for parameters of interest are presented.
The influence on predicted harmonic and distortion product generation of the position of the nonlinearity within cochlear micromechanical models
Authors: How Jacqueline A. , Elliott Stephen J. , Lineton Ben
Published: February 2010

Numerical techniques are used to explore the influence on the predicted basilar membrane (BM) response of the position of the nonlinearity within the micromechanical feedback loop of an active nonlinear cochlear model. This position is found to influence both the harmonic and distortion product spectra of the predicted BM response. The BM motion at the fundamental or primary frequencies is not significantly altered by the position of the nonlinearity, however, provided that the gain is appropriately adjusted. The observed effects are explained in terms of the frequency responses of the elements within the micromechanical feedback loop.
Crosstalk mitigation using adaptive time reversal
Authors: Song H. C. , Kim J. S. , Hodgkiss W. S. , Joo J. H.
Published: February 2010

Although the spatial focusing property of the conventional time reversal approach facilitates multiuser communications, there always is residual crosstalk between users. A recent paper [Kim and Shin, J. Acoust. Soc. Am. 115, 600–606 (2004)] proposed an adaptive active time reversal approach for simultaneous multiple focusing with minimal interference. This letter applies the adaptive approach to passive time reversal, multiuser communications for additional suppression of crosstalk among users. Experimental data at 3.5kHz with a 1-kHz bandwidth demonstrate as much as 6.5-dB improvement per user in terms of output signal-to-noise ratio for three-user communications over a 20-km range in 120-m deep shallow water.
Influence of inhibitory synaptic kinetics on the interaural time difference sensitivity in a linear model of binaural coincidence detection
Authors: Leibold Christian
Published: February 2010

Temporal correlations between the sound waves arriving at the two ears are used to extract the azimuthal position of sound sources. Nerve cells in the mammalian medial superior olive (MSO) that extract these binaural correlations are sensitive to interaural time differences (ITDs) in the range of about 10μs. These neurons receive inputs from the two ears via four pathways, two excitatory and two inhibitory ones. In this paper, a simple linear model is fitted to the frequency dependence of ITD sensitivity of MSO neurons, which is quantified by the two parameters, characteristic phase and characteristic delay. The fit parameters are the relative delays and the relative strengths of the two inhibitory pathways and thus specify the underlying ITD-detecting circuit assuming a non-Jeffress-like situation, i.e., no excitatory delay lines but phase-locked inhibition. The fitting procedure finds the parameters of these inhibitory pathways such that they account for a desired frequency dependence of ITD sensitivity. It is found that positive characteristic delays require a finite amount of ipsilateral inhibition that arrives at roughly the same time as ipsilateral excitation as well as contralateral inhibition that lags contralateral excitation so much that it effectively leads excitation of the next cycle.
Time-frequency and advanced frequency estimation techniques for the investigation of bat echolocation calls
Authors: Kopsinis Yannis , Aboutanios Elias , Waters Dean A. , McLaughlin Steve
Published: February 2010

In this paper, techniques for time-frequency analysis and investigation of bat echolocation calls are studied. Particularly, enhanced resolution techniques are developed and/or used in this specific context for the first time. When compared to traditional time-frequency representation methods, the proposed techniques are more capable of showing previously unseen features in the structure of bat echolocation calls. It should be emphasized that although the study is focused on bat echolocation recordings, the results are more general and applicable to many other types of signal.
Recognition of interrupted sentences under conditions of spectral degradation
Authors: Chatterjee Monita , Peredo Fabiola , Nelson Desirae , Başkent Deniz
Published: February 2010

Cochlear implant (CI) and normally hearing (NH) listeners’ recognition of periodically interrupted sentences was investigated. CI listeners’ scores declined drastically when the sentences were interrupted. The NH listeners showed a significant decline in performance with increasing spectral degradation using CI-simulated, noise-band-vocoded speech. It is inferred that the success of top-down processes necessary for the perceptual reconstruction of interrupted speech is limited by even mild degradations of the bottom-up information stream (16 and 24 band processing). A hypothesis that the natural voice-pitch variations in speech would help in the perceptual reconstruction of the sentences was not supported by experimental results.
Auditory-model based robust feature selection for speech recognition
Authors: Koniaris Christos , Kuropatwinski Marcin , Kleijn W. Bastiaan
Published: February 2010

It is shown that robust dimension-reduction of a feature set for speech recognition can be based on a model of the human auditory system. Whereas conventional methods optimize classification performance, the proposed method exploits knowledge implicit in the auditory periphery, inheriting its robustness. Features are selected to maximize the similarity of the Euclidean geometry of the feature domain and the perceptual domain. Recognition experiments using mel-frequency cepstral coefficients (MFCCs) confirm the effectiveness of the approach, which does not require labeled training data. For noisy data the method outperforms commonly used discriminant-analysis based dimension-reduction methods that rely on labeling. The results indicate that selecting MFCCs in their natural order results in subsets with good performance.
Orienting attention during phonetic training facilitates learning
Authors: Pederson Eric , Guion-Anderson Susan
Published: February 2010

The role of consciously directed attention toward speech input in learning has not yet been determined. Previous phonetic learning studies have manipulated acoustic signals and response feedback, but not conscious control over attentional orienting. This study tests whether directed attention facilitates learning of phonetic information. Two monolingual English-speaking groups were trained with feedback on the same auditory stimuli: Hindi words. One group was instructed to attend to the consonants and the other to the vowels. The consonant-oriented group, but not the vowel-oriented group, demonstrated post-training improvement in consonant perception, confirming a role for consciously directed attentional mechanisms during phonetic learning.
A non-linear three-dimensional model for quantifying microbubble dynamics
Authors: Patil Abhay V. , Reynolds Paul , Hossack John A.
Published: February 2010

A three-dimensional non-linear model for simulating microbubble response to acoustic insonation is presented. A 1 μm radius microbubble stimulated using positive and inverted 2.4 MHz pulses produced radius-time curves that matched (error <10%) with the experimental observation. A bound 2.3 μm radius microbubble insonated using 2.25 MHz 6 cycle pulse was observed to oscillate with max/min oscillations 45% lower than that of the free microbubble, this correlated (∼10% error) with the observations of Garbin et al. [Appl. Phys. Lett. 90, 114103 (2007)]. The adherent microbubble oscillated asymmetrically in the plan view and symmetrically in the elevation view, consistent with the previous experimental results.
Retromer Is Required for Apoptotic Cell Clearance by Phagocytic Receptor Recycling
Authors: Chen Didi , Xiao Hui , Zhang Kai , Wang Bin , Gao Zhiyang , Jian Youli , Qi Xiaying , Sun Jianwei , Miao Long , Yang Chonglin
Published: February 2010

Corpse-Sorting Machinery

Phagocytosis of apoptotic cells is an integral part of the cell death program and plays critical roles in tissue remodeling, suppression of inflammation, and regulation of immune responses. The clearance of cell corpses requires their engulfment and subsequent degradation by phagocytic cells. During this process, receptors of the CED-1 family play a central role in recognizing cell corpses, transducing engulfment signals, and initiating the maturation of phagosomes containing apoptotic cell corpses. Retromer is a multisubunit protein complex conserved from yeast to mammals that mediates retrograde transport of transmembrane cargo from the endosome to the trans-Golgi network. Failure in recycling these proteins leads to their delivery to lysosomes where they are degraded.

Chen
et al.

(p.
1261
, published online 4 February) report that the
Caenorhabditis elegans
retromer complex is essential for the phagocytosis of CED-1 and thus for the clearance of apoptotic cells.
A new species of aplanosporic Haptoglossa, H. beakesii, with vesiculate spore release
Authors: Glockling S. L. , Serpell L. C.
Published: February 2010

A new species of Haptoglossa , Haptoglossa beakesii sp. nov., a nematode parasite found in a sample of compost and rabbit dung at the University of Sussex campus, is described. The species, which infects nematodes of the genus Rhabditis , is unusual because it releases non-motile spores into a retaining vesicle. Aspects of the development and reproduction of the species are illustrated with light microscopy and transmission electron microscopy (TEM). TEM revealed a typical multinucleate thallus which cleaved into un-walled aplanospore initials. Each aplanospore contained a central nucleus closely surrounded by mitochondria and with peripheral dense body vesicles (DBV) and distinctive, layered, encystment vesicles. Aplanospores were expelled into a fine vesicle which later broke down to release cysts. Cysts germinated to produce infective gun cells.
Classification of strains of Fusarium oxysporum on the basis of vegetative compatibility
Authors: Puhalla John E.
Published: February 2010

Twenty-one strains of Fusarium oxysporum were classified on the basis of vegetative compatibility or the ability to form hetcrokaryons. Heterokaryon formation was demonstrated by pairing mutants that were unable to reduce nitrate. These "nit mutants" could be recovered without mutagen treatment from selective media containing KClO3. On Czapek's minimal medium the nit mutants had a radial growth rate like that of wild type, but their colonies were very thin. Two genetically different nit mutants were recovered in each of the 21 strains and paired in all combinations on minimal medium. Heterokaryon formation was indicated by dense growth where the two mutant colonies touched. As a result, 16 vegetative compatibility groups (VCGs) were defined such that only strains in the same VCG were vegetatively compatible. In no case was a strain assignable to more than one VCG. There was some evidence for a correlation between VCG and forma specialis. An evolutionary model to explain this correlation is proposed. Vegetative compatibility may be a fast and easy way to distinguish pathotypes of F. oxysporum.
Studies in the genus Strossmayeria (Helotiales). 5. Conidia and conidiogenesis in Pseudospiropes: a light and electron microscope investigation
Authors: Iturriaga Teresita , Israel Herbert W.
Published: February 2010

Conidiogenesis and conidial morphology in two Pseudospiropes species, anamorphs of two unnamed Strossmayeria species, were studied using light microscopy and scanning electron microscopy, and for one of these, transmission electron microscopy. Conidiogenesis is clearly holoblastic. In these species there are approximately 10 cells per conidium, the apical and basal ones being darker than the others. A gel surrounds the conidium, and what probably is a gelatinous appendage is seen at its apex. The conidial wall is composed of at least eight layers, the exterior surface being distinctly poroid. There are columnar irregularities in the conidial walls. These morphological features have potential taxonomic importance.
Synthesized ectomycorrhizae of aspen: fungal genus level of structural characterization
Authors: Godbout C. , Fortin J. A.
Published: February 2010

The ability of Populus tremuloides Michx. to form ectomycorrhizae with identified species of fungi was investigated using a pouch technique. Twenty-nine out of 54 fungus species formed ectomycorrhizae on aspen seedlings. Aspen seems to display little specificity for ectomycorrhizal fungi. Only epidermal Hartig nets were observed in the synthesized ectomycorrhizae and periepidermal ones were frequently encountered. Structural and morphological characteristics of ectomycorrhizae are presented by genus of mycorrhizal fungi. This grouping of characters by genus seems possible independently of the host plant. The classification of ectomycorrhizae is viewed in a new way in which structural types would be taxonomically related to the genus of the fungal symbiont.
The ultrastructure of plasmodia, sporangia, and cystosori of Ligniera verrucosa (Plasmodiophoromycetes)
Authors: Miller Charles E. , Martin Robert W. , Dylewski Daniel P.
Published: February 2010

The ultrastructure of plasmodia, sporangia, and cystosori of Ligniera verrucosa Maire and Tison is described and compared with that of other plasmodiophorids. Sporangiogenic plasmodia cleave into multilobed sporangia. The contents of each sporangial lobe cleaves to form secondary zoospores, which escape the sporangium by swimming through adjacent lobes after walls between lobes break down. Certain peripherally situated lobes do not form zoospores and, after expelling their undifferentiated contents, function as exit tubes during zoospore emergence. Plasmodia contained several large, membrane-bound vacuoles of unknown function. The taxonomy of the genus Ligniera and its species is discussed. Ligniera is a good and valid taxon.
Genetic analysis and mapping of a thermosensitive genic male sterility gene,tms6(t), in rice (Oryza sativaL.)
Authors: Liu Xia , Li Xihong , Zhang Xin , Wang Songwen
Published: February 2010

Thermosensitive genic male-sterile (TGMS) rice is widely used in hybrid rice production. Because of its specific temperature requirement, it can be used only in a narrow rice-growing zone in Asia. A newly discovered TGMS line, G20S, has an opposite phenotype compared with normal TGMS lines. G20S is completely sterile when the temperature is lower than 29.5 °C. Thus, it can be widely used in a larger area. Genetic analysis indicated that the sterility of G20S was controlled by a single recessive gene that was named tms6(t). An F2population from the cross between G20S and Jing226 was developed and used for molecular mapping of the tms6(t) gene. The simple sequence repeat technique, combined with bulked segregant analysis, was used to screen markers linked to the target gene, and linkage markers such as RM216, RM2504, RM3152, and RM4455 were identified. These markers are all located on chromosome 10; therefore, tms6(t) was subsequently mapped on chromosome 10. Co-segregation analysis using the F2population showed that two of these markers, RM3152 and RM4455, were closely linked to tms6(t) at distances of 3.00 cM and 1.10 cM, respectively. Additionally, integration of the genetic and physical maps showed that there were 15 BAC/PAC clones overlapping between RM3152 and RM4455, and tms6(t) was mapped to an interval of 1455 kb.
ON THE CELL WALLS OF DIMORPHIC FUNGI CAUSING SYSTEMIC INFECTIONS
Authors: Blank F.
Published: February 2010

Cultures of the mycelial and tissue-like growth phases of Blastomyces dermatitidis, Paracoccidioides brasiliensis, Histoplasma capsulatum, and Sporotrichum Schenckii were extracted and oxidized as described by Scholl in 1908. Debye–Scherrer diagrams of the so prepared cell walls show the presence of chitin in both growth phases of each fungus investigated, and give no evidence of the presence of cellulose or another high polymeric substance in the membranes. Nitrogen determinations of the same material corroborate these findings. Electron-microscopic investigations of the isolated chitin of Blastomyces dermatitidis did not reveal any substantial difference in the submicroscopic structures of the framework of the mycelial and yeast-like growth phases.
THE SUCCINOXIDASE SYSTEM INASPERGILLUS NIGER
Authors: Martin S. M.
Published: February 2010

The succinoxidase system of Aspergillus niger differs from that of avian and mammalian tissues in its greater lability during preparation and storage but is similar in its sensitivity to malonate, cyanide, azide, and B.A.L., its association with cell particles, and its single pH optimum at pH 7.3. The system is not inhibited by arsenite in concentrations up to 0.01 M.
LISTERIA MONOCYTOGENES—A STUDY OF TWO STRAINS ISOLATED FROM HUMAN LISTERIOSIS
Authors: Jaeger Robert F. , Myers Donald M.
Published: February 2010

Studies on two strains of L. monocytogenes isolated from human patients, have been reported. The 1949 and the 1951 strains are serologically similar but have slight biochemical variations. Cultures grown at temperatures ranging from 2.8 °C. to 5 °C. showed greater virulence and antigenicity as well as morphological differences when compared with cultures grown at 37 °C. Both the 1949 and 1951 strains were sensitive to penicillin in concentrations between 0.09 to 0.18 and 1.50 to 3.12 units per ml. respectively. They were not sensitive to sulphadiazine or sulphathiazole in concentrations up to 20 mgm. Per ml. Both strains produced an antigenic (lipoid-like) surface substance when extracted with chloroform and ether, which, when injected into rabbits, produced a monocytic response in the peripheral blood. A heat-killed vaccine protected guinea pigs from lethal doses of the Listeria organism, whereas control guinea pigs injected with the same number of living organisms died with typical symptoms. Partial immunity is demonstrable by the fact that rabbits recovering following penicillin therapy resisted reinfection for a period of at least one hundred and ninety days. Further work is being carried on to determine whether there is a relationship between the heat-labile "L" surface antigen and virulence.
THE USE OF BACTERIOPHAGE OF XANTHOMONAS PHASEOLI IN DETECTING INFECTION IN BEANS, WITH OBSERVATIONS ON ITS GROWTH AND MORPHOLOGY
Authors: Katznelson H. , Sutton M. D. , Bayley S. T.
Published: February 2010

A study was made of certain factors affecting the use of a phage–plaque-count technique for detecting in bean seed the organism causing common bacterial blight, Xanthomonas phaseoli (Erw. Smith) Dowson. It was found that overgrowth of the fluid test cultures with contaminating bacteria from the seed or from soil did not interfere appreciably with phage adsorption or multiplication in the presence of host cells. Such samples required centrifugation prior to testing in order that plaques might be readily discernible on agar plates. The phage was adsorbed specifically only by cells of X. phaseoli. Tests with a variety of media showed that nutrient broth was adequate for the purposes of the phage–plaque-count technique. An incubation time of at least 24 hr. for phage and sample was shown to be desirable. Out of 75 samples tested in quadruplicate, 50% were found to be infected with the pathogen in varying degrees. Several samples gave positive reactions by means of this plaque-count method under conditions which were quite unfavorable for isolation of the pathogen by the usual methods.One-step growth studies with X. phaseoli-phage indicated a low order of adsorption, a latent period of 30 to 45 min., a rise period of approximately 30 min., and a burst size of 40 for stationary cultures and 30 for shake cultures. Electron microscopy of X. phaseoli-phage preparations revealed a particle with a dense head 60 mμ in diameter and a tail 170 to 190 mμ long and 10 to 15 mμ wide.
A COMPARISON OF MICROBIAL ACTIVITY IN AN ONTARIO FOREST SOIL UNDER PINE, HEMLOCK, AND MAPLE COVER
Authors: Chase F. E. , Baker G.
Published: February 2010

Soil samples, taken by horizons, were obtained from the University of Toronto Forest near Dorset under stands of maple, hemlock, and pine. Counts of bacteria, actinomycetes, and fungi made by the plate method indicated that in general the organic layer contained the largest population, and also that in the organic layer under conifers the fungi exceeded the combined counts of the other two groups, whereas under maple the bacteria predominated. Using the perfusion method, nitrification did not occur to any extent in these forest soil samples except when lime was added, and even then nitrification started very slowly unless a few crumbs of garden soil were added, presumably as a source of active nitrifying bacteria.
EXPERIMENTS ON THE METHANE BACTERIA IN SLUDGE
Authors: Mylroie R. L. , Hungate R. E.
Published: February 2010

An agar culture method for determining the numbers of methanogenic bacteria in sludge was developed. Hydrogen and carbon dioxide were provided as substrate and palladium as a reduction catalyst. Sodium sulphide could also be used for reducing the medium. A methanogenic organism could be identified by correlating methane production with presence of a particular type of colony which was the most abundant. Fifteen strains which were pure cultured were all similar and were classified as Methanobacterium formicicum. The culture count for methane bacteria in sludge ranged between 105 and 108 per ml. The rate of fermentation and the efficiency of conversion of substrate into cell material were studied. Presence of an acetate-fermenting methanogenic organism was established but no pure cultures could be obtained. Methanobacterium formicicum appeared to be the only methane producer growing in the dilution series used for counts.
STUDIES ON THE FLAGELLA OF ALGAE: V. SEROLOGY OF PARALYZED MUTANTS OF CHLAMYDOMONAS
Authors: Mintz Rita H. , Lewin Ralph A.
Published: February 2010

No significant serological differences could be detected between the flagella of wild-type cells of Chlamydomonas moewusii and those of paralyzed mutants.
EVIDENCE FOR MULTIPLE COMPONENTS IN MICROBIAL CELLULASES
Authors: Gilligan William , Reese Elwyn T.
Published: February 2010

Evidence is offered for the existence of several cellulolytic components in the extracellular filtrates of microorganisms. Components separated chromatographically differ in their relative activities on native cotton, swollen cellulose, and CMC. A synergistic effect was obtained when separated components were recombined.
CLOSTRIDIUM BOTULINUM TYPE E TOXIN AND TOXOID
Authors: Barron A. L. , Reed G. B.
Published: February 2010

A strain of Clostridium botulinum Type E in a beef heart infusion – peptone broth yields moderate amounts of toxin when grown at 30 °C. but fails to produce toxin at 37°. When grown in a cellophane sac suspended in a similar medium, at 30 °C, there is a 5- to 10-fold increase in the yield of toxin. Toxoid has been prepared from the high potency cellophane produced toxin by clarification with charcoal, Mandler filtration, and detoxification with 0.3% formalin at 30 °C. for 20 days. Three doses of the fluid toxoid protects mice against 500 M.L.D. of homologous toxin. One dose of the same toxoid adsorbed on alum affords the same level of protection as three doses of the fluid toxoid. Mixing Type E toxoid with equal amounts of Types A and B in vitro augments the antigenic action of the Type E toxoid.
ON THE CHEMICAL COMPOSITION OF THE CELL WALLS OF THE ACTINOMYCETALES AND ITS RELATION TO THEIR SYSTEMATIC POSITION
Authors: Avery R. J. , Blank F.
Published: February 2010

Washed and dried cultures of Actinomyces bovis, A. israeli, Nocardia asteroides, Streptomyces albus, S. griseus, and Micromonospora chalcea were treated as described by Scholl (1908). Neither chitin nor cellulose, which form the framework of the Eumycetes, could be isolated. Therefore, from this chemical point of view the Actinomycetales have nothing in common with the true fungi, but rather with bacteria. These findings are in complete agreement with the morphological features of the Actinomycetales which indicate their place among the bacteria.