bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of scalloping depth on the sound generated by turbofan engine lobed mixers
Authors: Gong Hao , Habibi Kaveh , Mongeau Luc
Published: May 2013

The growing stringency of community noise regulations for commercial turbo-fan engine requires the development of effective jet noise suppression configurations. The large number of geometrical design parameters for lobed mixers precludes trial and error experimental studies. In this study, a robust computational tool was used to investigate the effects of the scalloping depth on sound radiated from a lobed mixer. The near field sound and flow were simulated using a flow solver based on the Lattice Boltzmann Method (LBM). The far field radiated sound was predicted using the Ffwocs William-Hawkings (FWH) surface integral method. One baseline confluent nozzle and three nozzles with varying scalloping depth were considered. Low Mach number flow was assumed, with operating conditions selected to best approach conditions for actual engines. The effects of an outer mean flow to simulate forward flight were not included. The increased scalloping depth was found to enhance mixing and to reduce noise levels in the mid-to-high frequency range, as anticipated. Results were in qualitative agreement with available experimental results.
An experimental investigation on the near-field turbulence for an airfoil with trailing-edge serrations and an owl specimen
Authors: Xu Kunbo , Qiao Weiyang , Ji Liang , Chen Weijie
Published: May 2013

The ability to fly silently of most owl species has long been a source of inspiration for finding solutions for quieter aircraft and turbomachinery. This study concerns the mechanisms of the turbulence for an airfoil with trailing-edge serrations and a real owl specimen . the turbulence spatio-temporal information are measured with 3D hot-wire. The experiment is carried out in the Northwestern Polytechnical University low speed open jet wind tunnel on the SD2030 airfoil. Mach numbers range up to 0.3, with the Reynolds numbers from 1.9e+4 to 2.6e+5, the angle of attack α at −50, 00, and +50, the sawtooth of λ/h = 0.2. The individual trailing-edge serrations tips and valleys could be seen in the wake region. It is showed the spreading rate of the wake and the decay rate of the wake centerline velocity deficit increased with serrated edge compared to the straight edge. It is also found that the turbulence peak occurs further from the airfoil surface in the presence of the serrations, and the serrations generate additional horseshoe vortices shed in the near wake. However, the boundary layer statistics slightly upstream from the TE are not influenced by the serrations.
Acoustic analysis from pentatonic Angklung
Authors: Sudarsono Anugrah S. , Merthayasa I Gde Nyoman
Published: May 2013

Angklung is traditional music instruments from Indonesia made from bamboo. Pentatonic angklungs are angklung that only have five notes. The notes are from the traditional Sundanese scale. Experiment was done to analyze spectral, temporal, and spatial parameters from pentatonic angklung. Spectral analysis was done by analyze the pitch and timbre. Temporal analysis was done by analyze the sound envelope and from τe parameter from the music. Spatial analysis was done from measurement of the sound energy by multiple microphones in semi anechoic room. Pitch and timbre were analyzed with Fast Fourier Transform from 29 angklungs. It was found from spectral analysis that angklung has overtone 1.44 f0, 2 f0, 3.47 f0, 6.31 f0, and 7 f0 with f0 as the fundamental frequency. The scales of the notes are very different from western scale and pentatonic angklung has four different scale intervals. Sound envelope analysis shows that angklung has attack time 192–179 ms and release time 346–902 ms. τe is a parameter that correlated with bandwidth frequency, lower value of τe correlated with wider bandwidth frequency. The value of τe from pentatonic angklung music is between 17 and 50 ms. The value was measured from six songs played by pentatonic angklung. Spatial analysis shows that the direction of sound headed to the left front side of angklung.
Reproduction of sound source directionality in reduced scale model
Authors: Lisot Aline , Bertoli Stelamaris R.
Published: May 2013

The study of acoustic phenomena through reduced scale models is a useful tool for predicting the acoustic performance of closed and outdoor environments. When using reduced scale models, begins a process of constructive adequacy details of the study environment and sound source characteristics, reproducing its level and directionality. It is presented in this paper, a study on the reproduction of sound source directionality with application in outdoor reduced scale model. The sound source is an electric power converting substation. The directionality of this source was calculated using sound pressure levels measured, in 1/3 octave frequency bands between 50 Hz and 12.5 kHz, in 24 points positioned on a circle located around of the sound source. The sound was recorded in a point outside the circle for later playback. For playback of the sound signal, the noise was emitted in each monitoring direction, considering in each one the directionality through the signal equalization. The reduced scale used in the model was 1:5 and, based on this, it was transposed the frequencies of the signal. It was concluded that the sound source used in the reduced scale can be an efficient tool for reproduction of the directionality characteristics of the source.
Validation of the CSA Z107,56 standard method for the measurement of noise exposure from headsets
Authors: Behar Alberto , Nespoli Gabe , Defrancesco-Loria Tristan , Russo Frank
Published: May 2013

The last section of the CSA Standard CAN/CSA-Z107.56-06 (R2011)—Procedures for the Measurement of Occupational Noise Exposure—deals with communication headsets. This section is typically applied in retail, call centers, airport control towers, and other settings where an operator is exposed to background noise while communicating with a headset. Because the user adjusts the volume to hear speech comfortably, the total equivalent sound level is a function of the level of the background noise minus the attenuation provided by the headset, plus a comfortable signal/noise ratio, estimated to be 13.5 dBA. Despite ample research demonstrating the role of spectral and temporal factors in speech masking, the standard is applied consistently regardless of the type of background.
Sonochemical synthesis of nano-cocrystals
Authors: MacGillivray Leonard R. , Bucar Dejan-Kresimir , Sander John R. , Elacqua Elizabeth
Published: May 2013

Cocrystals are multicomponent solids with organic molecules assembled in combination to form a crystalline solid with properties different than the individual components. A cocrystal typically consists of a target molecule crystallized with a second molecule, or cocrystal former, employed to influence properties of the target (e.g., solubility). The conformer interacts with the target via intermolecular forces (e.g., hydrogen bonds) that hold the components together. The modularity of a cocrystal makes such solids attractive for applications where fine-tuning of properties is important (e.g., optical). In this presentation, we describe the use of sonochemistry to form cocrystals of nanoscale dimensions. In contrast to single-component solids, cocrystals present a fundamentally different challenge with respect to those reprecipitation methods used to form nanocrystals since the components of a cocrystal will tend to exhibit different solubilities. We show that sonochemistry affords nano-cocrystals with properties (e.g., reactivity) that contrast solids of macroscale dimensions. Related applications of sonochemistry to afford single-component nanocrystals will also be presented.
Enhancing biofuel production by ultrasonics
Authors: Grewell David , Montalbo-Lomboy Melissa , Chand Priyanka
Published: May 2013

This work evaluated the use of high-powered ultrasonics to enhance biofuel production in terms of efficiency and costs. A wide range of feed stocks, including switch grass, corn stover, and soft wood, were studied. The effect of ultrasonic pretreatment on the removal of lignin for hydrolysis of starches and cellulose to fermentable sugars was studied. It was found that many of the pretreatments were very successful in enhancing lignin removal. For example, time of dissolution of lingo-cellulosic biomass in ionic liquids was reduced from hours to minutes accompanied by a significant decrease in energy consumption compared to mechanical stirring. In addition, it was found that hydrolysis of corn starch could be greatly accelerated utilizing ultrasonics. Economic models showed that the technology, once implemented, would have a payback period of less than one year. The work also focused on biodiesel production. It was seen that ultrasonics accelerated the transesterification process so that soy bean oil could be converted to biodiesel in less than a minute, compared to 45 min using traditional methods. It was shown that yeast grown from glycerin, a co-product of biodiesel production, could be extracted and simultaneously converted to biodiesel with ultrasonics in less than a minute, compared to traditional techniques that require multiple processes and relatively long cycle times (+1 h).
Microbial inactivation by ultrasound for enhanced food safety
Authors: Feng Hao , Zhou Bin , Lee Hyoungill , Li Yanfang , Park Hee Kyung , Palma Sindy , Pearlstein Arne
Published: May 2013

Inactivation of foodborne pathogens by power ultrasound provides an alternative to traditional thermal processing modalities, with potential for minimizing food-quality degradation. To enhance efficacy, ultrasonic treatment is often combined with other physical or chemical lethal factors, which serve to shorten treatment time and improve quality retention. The inactivation mechanisms, thermodynamic aspects, and kinetic modeling of ultrasonic microbial inactivation will be discussed. The critical issue of how to achieve a relatively uniform acoustic field distribution during treatment will be investigated by computer simulation and verified with microbial inactivation tests. Inactivation of foodborne pathogens in liquid foods, and surface decontamination of fresh produce and nuts, will be used as examples demonstrating the potential of ultrasound-assisted processes. Lastly, the effect of sonication treatment on food product quality and quality retention will be examined.
The analytical model of rheological fluid for vibration and noise control
Authors: Szary Marek L.
Published: May 2013

Rheological fluids (RF) also known as a controllable viscosity fluids (CVF) introduced in the area of vibration control of mechanical systems made possible a more efficient control of both: transient and continuous vibration. They are also used in design of sound barriers to control noise transmission loss and diaphragms for modification of noise absorption characteristics of sound absorbing materials. Their apparent viscosity is controllable by the use of external (electrical in electro-rheological ER or electromagnetic in magneto-rheological MR fluids) field. In the absence of applied external field, the RF exhibits Newtonian-like behavior. Applied external field changes this behavior and the RF shows in addition a yield shear stress which depends on strength of this field. In proposed model, the shear stress is expressed as a superposition of two components. One of them is proportional to the viscosity and relative velocity of a base fluid, and the second one, which depends on strength of applied external field. Modification of external field strength according to selected design parameter (velocity or time or distance—combination of them) allows to develop family of vibration or sound attenuating devices, which were not achievable before.
Modeling flow through the posterior glottal gap
Authors: Scherer Ronald , Frazer Brittany , Zhai Guangnian
Published: May 2013

The BGSU three mass model of phonation incorporates a posterior glottal gap. The airflow through the gap is governed by a simple hydraulic formula. The current study compares predictions of the gap size to the DC flow of three human subjects over two pitches at normal loudness. This work also explores the importance of the posterior gap by comparing extensive human mean subglottal pressure—mean flow—vocal process adduction data (from one subject) with the behavior of the model. The relation between glottal gap size to the DC flow for the three subjects was exceptionally strong (R2 = 0.99). The relatively linear pressure-flow relationships at specific adduction values for the human data are hypothesized to be mimicked by the model, with a reasonable relationship to the size of the posterior glottal gap. [Work support from NIH.]
Acoustic coupling during incomplete glottal closure and its effect on the inverse filtering of oral airflow
Authors: Zañartu Matías , Ho Julio C. , Mehta Daryush D. , Hillman Robert E. , Wodicka George R.
Published: May 2013

Inverse filtering of oral airflow using closed-phase linear prediction is expected to preserve the effects of source-filter interactions in the glottal airflow pulse. Under incomplete glottal closure, the glottal airflow estimation is more challenging due to a lowered glottal impedance, increased subglottal coupling, and violated all-pole assumption. To account for these effects, a model-based inverse filtering scheme allowing for coupling between glottis and upper and lower airways was developed. Acoustic transmission in the tracts used a frequency-domain transmission line. A linearized, time-varying expression was used for the glottal impedance, along with a dipole representation. Synthetic vowels sounds and actual recordings were used to evaluate the proposed scheme. Subject-specific model parameters were obtained from simultaneous aerodynamic, acoustic, and high-speed videoendoscopic recordings of normal subjects uttering vowels with various degrees of glottal closure. Results illustrated that, even under incomplete glottal closure, the airflow entering the vocal tract preserved source-filter interactions and was comparable to that obtained using closed-phase linear prediction. The scheme also yielded an uncoupled glottal airflow that exhibited a clear pulse de-skewing, making it proportional to the glottal area. Cases with larger glottal gaps exhibited lower mean impedances and less pulse skewing, with airflow estimates proportional to the transglottal pressure drop.
Listeners’ sensitivity to talker differences in voice-onset-time: Phonetic boundaries and internal category structure
Authors: Theodore Rachel M. , Myers Emily B. , Lomibao Janice
Published: May 2013

Recent findings indicate that listeners are sensitive to talker differences in phonetic properties of speech, including voice-onset-time (VOT) in word-initial stop consonants. The current work extends our earlier research by examining the degree to which listeners adjust the initial mapping from acoustic signal to segmental representation on a talker-specific basis. Two groups of listeners are exposed to a talker producing “cane.” Word-initial VOTs are manipulated such that one group hears “cane” produced with short VOTs and the other group hears “cane” produced with relatively longer VOTs. Following training, listeners’ voicing boundary for a /g/-/k/ continuum is tested. In addition, listeners are tested on phonetic category space by rating members of the continuum for typicality as /k/. If listeners adjust segmental mapping to accommodate talker differences in phonetic properties of speech, then we expect to observe a displacement in the voicing boundaries in line with earlier exposure. Moreover, if this adjustment entails a comprehensive reorganization of phonetic category space, then the /k/ exemplars rated most prototypical will also be displaced for the two listener groups. These data will be discussed in terms of potential constraints on talker-specificity in spoken language processing.
Describing alternative articulations of the Spanish trill /r/ by ultrasound technology
Authors: Rivera-Campos Ahmed , Boyce Suzanne E.
Published: May 2013

The Spanish trill /r/ is typically described as having a single realization—that is, as the result of aerodynamic forces operating on a tongue tip/blade constriction placed midsagittally in the dental, alveolar, or postalveolar place of articulation, in such a way that air channels along the sides of the tongue open and close for multiple cycles of vibration. As with American English /ɹ/, this sound is acquired late by typically developing children and is frequently an element in articulatory disorders. As with American English /ɹ/, perceptually equivalent “correct” trill /r/’s may be realized differently by different speakers. Knowledge of these alternate “correct” realizations would clearly be helpful to clinicians and learners of Spanish. In this preliminary study, we report data from ultrasound images of individuals who speak different dialects of Spanish. Preliminary data suggests there are at least two different articulatory postures used when producing the Spanish trill /r/, one of which involves lateralization. These articulatory differences do not affect what native listeners categorize as perceptually correct Spanish trills.
Multidimensional scaling of English fricatives using the acoustic change complex of electroencephalogram recordings
Authors: Iverson Paul , Mulyak Marta , Wagner Anita
Published: May 2013

In electroencephalogram (EEG) recordings, there is a characteristic P1-N1-P2 complex after the onset of a sound, and a related complex, called the Acoustic Change Complex (ACC), when there is a change within a sound (e.g., a formant transition between two vowels). In the present study, the ACC was measured for all possible pairs of eight sustained voiced and voiceless English fricatives, in EEG recordings from native speakers of British English. The magnitude of the ACC was used as a similarity measure for multidimensional scaling (MDS), producing a two-dimensional perceptual space that related to both voicing and place of articulation. The results thus demonstrate that this combination of ACC and MDS can be effective for mapping multidimensional phonetic spaces at relatively early levels of auditory processing, which may be useful for evaluating the effects of language experience in adults and infants.
Nasality effects in word-final nasal clusters
Authors: Nguyen Emily
Published: May 2013

This study presents an acoustic analysis of the proposed phonological process of nasal deletion in English [Cohn (1993), Bybee (2001)] in which vowel-nasal consonant-oral consonant (VNC) sequences differ in the realization of the nucleus based on the voicing feature of the final oral consonant. Previous work has proposed that the nasal consonant in VNC[-voice] sequences, e.g., tent, is deleted resulting in the realization of a fully nasalized vowel followed by a voiceless oral consonant,ṼC[-voice]. This phonological process of nasal deletion is said not to take place in VNC[+voice] sequences, e.g., tend, resulting in the full realization of all segments. Data from 15 speakers of American English were analyzed, and nasal deletion rates for VNC[-voice] sequences were low (<12%). A further complication for this proposed phonological process is that vowel nasality differences between VNC[-voice] and VNC[+voice] sequences are small. A measure of vowel nasality, A1-P0, shows that while nasality is predicted to be constant from the onset of vowel production in VNC[-voice] sequences, statistical results show that vowels in both VNC[-voice] and VNC[+voice] sequences are progressively nasalized throughout production. Taken together, these findings suggest that nasal deletion is occasional and occurs due to phonetic implementation rather than a phonological process.
Articulatory overlap in English syllables with postvocalic /ɹ/
Authors: Walker Rachel , Proctor Michael
Published: May 2013

In General American English (GAE), only two full vowels [ɑ, ɔ] occur in syllables ending in [ɹ] plus a non-coronal consonant, e.g., , . An articulatory study of rhotic production by three speakers of GAE was conducted using real-time structural magnetic resonance imaging (rtMRI) [Narayanan et al. (2004)]. Subjects produced /ɹ/ in simple and complex syllable codas in a range of vocalic environments. Results show that the tongue dorsum shows the least movement in [-ɑɹ-] and [-ɔɹ-] sequences. This dorsal stability sheds light on why [ɑ] and [ɔ] are the only full vowels occurring before codas with /ɹ/ and a non-coronal consonant. English syllable rimes have been analyzed as maximally three timing units in length [Hammond (1999)]. Long vowels occupy two units, and most coda consonants occupy one unit, rendering rimes with long [ɑ]/[ɔ] followed by [ɹp] or [ɹk] problematic. We hypothesize that the high degree of overlap in the dorsal posture in [ɑɹ] and [ɔɹ] sequences allows their gestures to be partially blended and function like a diphthong that occupies two units in the rime. This study supports a view of maximal constituency in rimes with [ɹ] that takes articulatory overlap into account.
Cortical hemodynamic response patterns to normal and whispered speech
Authors: Remijn Gerard B. , Kikuchi Mitsuru , Yoshimura Yuko , Ueno Sanae , Shitamichi Kiyomi , Minabe Yoshio
Published: May 2013

Whispered speech is often used in direct person-to-person communication as a means to confidentiality. Compared with normally vocalized speech, whispered speech is predominantly unvoiced, i.e., produced without vocal fold vibration, and has no clear fundamental frequency. By using near-infrared spectroscopy (NIRS), we assessed cortical hemodynamic response patterns to normally vocalized and whispered speech in adult listeners (n = 13). Stimuli consisted of 20-s strings of Japanese word associations spoken by a female voice. Average oxygenated hemoglobin values (oxy-Hb) were obtained over two regions of interest (ROIs). Results showed that oxy-Hb values during the perception of normally vocalized speech were highest over the left temporal ROI, but not significantly different from values measured over other ROIs. Oxy-Hb values during whispered speech were highest over the right temporal ROI and significantly higher (p < 0.05) than those obtained over the left temporal ROI. No significant differences, however, were found in oxy-Hb comparisons between normally vocalized and whispered speech, although the right temporal ROI comparison bordered on significance, with whisper inducing the higher value. Together, the results seem to suggest that whispered speech is a potent catalyst of cortical hemodynamic activity, especially over the right temporal cortex, in spite of its relatively modest sound level as compared to normal speech.
Perception of vowel-inherent spectral change
Authors: Chiddenton Kathleen , Kiefte Michael
Published: May 2013

One family of theories regarding vowel perception suggests that onset and offset formant-frequencies are important for identification but that the shape of the transitions themselves is not perceptually important [e.g., Morrison and Nearey, J. Acoust. Soc. Am. 122, EL15–EL22 (2007)]. The present study determined just-noticeable-differences in deviations for linear formant trajectories. Diphthong-like stimuli were manipulated by inserting a point of inflection into the otherwise linear transition. Several parameters were manipulated including vowel duration, location of the inflection point in time, direction of formant change, and fundamental frequency. Data from the first experiment indicate that listeners are largely insensitive to deviations from linearity of formant trajectory but that deviations that fell outside the range of frequencies spanned by the onset and offset were detectable. However, a second experiment in which only the first half of stimuli were presented gave different results. Results from these experiments along with several hypotheses are presented. [Work supported by SSHRC.]
Computing the singular value decomposition in parallel on graphics processing units using a one-sided Jacobi method
Authors: Romer Michael V.
Published: May 2013

The singular value decomposition (SVD) provides a robust means of determining the dominant modes in a collection of signals that can then be used in adaptive beamforming to suppress loud interferers that would otherwise cover signals of interest. However, on serial architectures this decomposition can quickly become a bottleneck, hindering the real-time performance of the beamformer. Commercial off-the-shelf graphics processing units (GPUs) are an inexpensive means of adding parallel processing capabilities to a system and can reduce computation time by several orders of magnitude. The following work presents an algorithm that computes the full SVD of a dense matrix in parallel using a one-sided Jacobi method on a standard GPU. Both the runtime performance and relative accuracy of the algorithm are compared to the Intel Math Kernel Library (MKL) LAPACK implementation run on a CPU. Potential limitations to this approach due to restrictions imposed by the hardware are also discussed.
Interactive gpu-based sound auralization in dynamic scenes
Authors: Mo Qi , Taylor Micah , Chandak Anish , Lauterbach Christian , Schissler Carl , Manocha Dinesh
Published: May 2013

We present an auralization algorithm for interactive virtual environments with dynamic objects, sources, and listener. Our approach uses a modified image source method that computes propagation paths combining direct transmission, specular reflections, and edge diffractions up to a specified order. We use a novel multi-view raycasting algorithm for parallel computation of image sources on GPUs. Rays that intersect near diffracting edges are detected using barycentric coordinates and further propagated. In order to reduce the artifacts in audio rendering of dynamic scenes, we use a high order interpolation scheme that takes into account attenuation, crossfading, and delay. The resulting system can perform auralization at interactive rates on a high-end PC with NVIDIA GTX 280 GPU with 2–3 orders of reflections and 1 order of diffraction. Overall, our approach can generate plausible sound rendering for game-like scenes with tens of thousands of triangles. We observe more than an order of magnitude improvement in computing propagation paths over prior techniques.
Science Signaling
Podcast: 7 May 2013
Authors: Bading Hilmar , VanHook Annalisa M.
Published: May 2013

Calcium signaling is required for long-term memory in fruit flies.
Efficacy of Liposomal Amphotericin B and Posaconazole in Intratracheal Models of Murine Mucormycosis
Authors: Luo Guanpingsheng , Gebremariam Teclegiorgis , Lee Hongkyu , French Samuel W. , Wiederhold Nathan P. , Patterson Thomas F. , Filler Scott G. , Ibrahim Ashraf S.
Published: May 2013

Mucormycosis is a life-threatening fungal infection almost uniformly affecting diabetics in ketoacidosis or other forms of acidosis and/or immunocompromised patients. Inhalation of
Mucorales
spores provides the most common natural route of entry into the host. In this study, we developed an intratracheal instillation model of pulmonary mucormycosis that hematogenously disseminates into other organs using diabetic ketoacidotic (DKA) or cyclophosphamide-cortisone acetate-treated mice. Various degrees of lethality were achieved for the DKA or cyclophosphamide-cortisone acetate-treated mice when infected with different clinical isolates of
Mucorales
. In both DKA and cyclophosphamide-cortisone acetate models, liposomal amphotericin B (LAmB) or posaconazole (POS) treatments were effective in improving survival, reducing lungs and brain fungal burdens, and histologically resolving the infection compared with placebo. These models can be used to study mechanisms of infection, develop immunotherapeutic strategies, and evaluate drug efficacies against life-threatening
Mucorales
infections.
Pharmacodynamics Modeling To Optimize Dosage Regimens of Sulbactam
Authors: Jaruratanasirikul Sutep , Wongpoowarak Wibul , Aeinlang Nanchanit , Jullangkoon Monchana
Published: May 2013

The aim of this study was to reveal population pharmacokinetics and assess the efficacies of various dosage regimens of sulbactam in terms of the probability of target attainment with this agent over a range of MICs. Monte Carlo simulations were performed to determine the probability of attaining specific pharmacodynamic targets. The results indicated that a regimen consisting of a 4-h infusion of 3 g of sulbactam every 8 h would be an alternative treatment option for less-susceptible pathogens.
Fetal Safety of Macrolides
Authors: Bahat Dinur Anat , Koren Gideon , Matok Ilan , Wiznitzer Arnon , Uziel Elia , Gorodischer Rafael , Levy Amalia
Published: May 2013

Macrolide antibiotics are largely used in pregnancy for different bacterial infections. Their fetal safety has been studied by several groups, yielding opposing results. In particular, there have been studies claiming an association between macrolides and cardiovascular malformations. Exposure in early infancy has been associated with pyloric stenosis and intussusception. This has led to an avoidance in prescribing macrolides to pregnant women in several Scandinavian countries. The Objectives of the present study was to investigate the fetal safety of this class of drug by linking a large administrative database of drug dispensing and pregnancy outcome in Southern Israel. A computerized database of medications dispensed from 1999 to 2009 to all women registered in the Clalit health maintenance organization in southern Israel was linked with two computerized databases containing maternal and infant hospitalization records. Also, medical pregnancy termination data were analyzed. The following confounders were controlled for: maternal age, ethnicity, maternal pregestational diabetes, parity, and the year the mother gave birth or went through medical pregnancy termination. First- and third-trimester exposures to macrolide antibiotics as a group and to individual drugs were analyzed. During the study period there were 105,492 pregnancies among Clalit women that met the inclusion criteria. Of these, 104,380 ended in live births or dead fetuses and 1,112 in abortion due to medical reasons. In the first trimester of pregnancy, 1,033 women were exposed to macrolides. There was no association between macrolides and either major malformations [odds ratio (OR), 1.08; 95% confidence interval (CI), 0.84 to 1.38)] or specific malformations, after accounting for maternal age, parity, ethnicity, prepregnancy diabetes, and year of exposure. During the third trimester of pregnancy, 959 women were exposed to macrolides. There was no association between such exposure and perinatal mortality, low birth weight, low Apgar score, or preterm delivery. Similarly, no associations were demonstrated with pyloric stenosis or intussusception. Use of macrolides in the first trimester of pregnancy is not associated with an increased risk of major malformations. Exposure in the third trimester is not likely to increase neonatal risks for pyloric stenosis or intussusception in a clinically meaningful manner.
H-NS Plays a Role in Expression of Acinetobacter baumannii Virulence Features
Authors: Eijkelkamp Bart A. , Stroeher Uwe H. , Hassan Karl A. , Elbourne Liam D. H. , Paulsen Ian T. , Brown Melissa H.
Published: May 2013

Acinetobacter baumannii
has become a major problem in the clinical setting with the prevalence of infections caused by multidrug-resistant strains on the increase. Nevertheless, only a limited number of molecular mechanisms involved in the success of
A. baumannii
as a human pathogen have been described. In this study, we examined the virulence features of a hypermotile derivative of
A. baumannii
strain ATCC 17978, which was found to display enhanced adherence to human pneumocytes and elevated levels of lethality toward
Caenorhabditis elegans
nematodes. Analysis of cellular lipids revealed modifications to the fatty acid composition, providing a possible explanation for the observed changes in hydrophobicity and subsequent alteration in adherence and motility. Comparison of the genome sequences of the hypermotile variant and parental strain revealed that an insertion sequence had disrupted an
hns
-like gene in the variant. This gene encodes a homologue of the histone-like nucleoid structuring (H-NS) protein, a known global transcriptional repressor. Transcriptome analysis identified the global effects of this mutation on gene expression, with major changes seen in the autotransporter Ata, a type VI secretion system, and a type I pilus cluster. Interestingly, isolation and analysis of a second independent hypermotile ATCC 17978 variant revealed a mutation to a residue within the DNA binding region of H-NS. Taken together, these mutants indicate that the phenotypic and transcriptomic differences seen are due to loss of regulatory control effected by H-NS.
Bovine Respiratory Syncytial Virus and Histophilus somni Interaction at the Alveolar Barrier
Authors: Agnes J. T. , Zekarias B. , Shao M. , Anderson M. L. , Gershwin L. J. , Corbeil L. B.
Published: May 2013

Our previous studies showed that
Histophilus somni
and bovine respiratory syncytial virus (BRSV) act synergistically
in vivo
to cause more severe bovine respiratory disease than either agent alone causes. Since
H. somni
surface and secreted immunoglobulin binding protein A (IbpA) causes retraction of bovine alveolar type 2 (BAT2) cells and invasion between BAT2 cells
in vitro
, we investigated mechanisms of BRSV-plus-
H. somni
infection at the alveolar barrier. BRSV treatment of BAT2 cells prior to treatment with IbpA-rich
H. somni
concentrated culture supernatant (CCS) resulted in increased BAT2 cell rounding and retraction compared to those with either treatment alone. This mimicked the increased alveolar cell thickening in calves experimentally infected with BRSV followed by
H. somni
compared to that in calves infected with BRSV or
H. somni
alone. BRSV-plus-
H. somni
CCS treatment of BAT2 cells also enhanced paracellular migration. The effect of matrix metalloproteinases (MMPs) was investigated as well because microarray analysis revealed that treatment with BRSV plus
H. somni
synergistically upregulated BAT2 cell expression of
mmp1
and
mmp3
compared to that in cells treated with either agent alone. Enzyme-linked immunosorbent assay (ELISA) confirmed that MMP1 and MMP3 protein levels were similarly upregulated. In collagen I and collagen IV (targets for MMP1 and MMP3, respectively) substrate zymography, digestion was increased with supernatants from dually treated BAT2 cells compared with those from singly treated cells. Enhanced breakdown of collagen IV in the basal lamina and of fibrillar collagen I in the adjacent interstitium in the dual infection may facilitate dissemination of
H. somni
infection.
Human Leukocyte Antigens and Cellular Immune Responses to Anthrax Vaccine Adsorbed
Authors: Ovsyannikova Inna G. , Pankratz V. Shane , Vierkant Robert A. , Pajewski Nicholas M. , Quinn Conrad P. , Kaslow Richard A. , Jacobson Robert M. , Poland Gregory A.
Published: May 2013

Interindividual variations in vaccine-induced immune responses are in part due to host genetic polymorphisms in the human leukocyte antigen (HLA) and other gene families. This study examined associations between HLA genotypes, haplotypes, and homozygosity and protective antigen (PA)-specific cellular immune responses in healthy subjects following immunization with Anthrax Vaccine Adsorbed (AVA). While limited associations were observed between individual HLA alleles or haplotypes and variable lymphocyte proliferative (LP) responses to AVA, analyses of homozygosity supported the hypothesis of a “heterozygote advantage.” Individuals who were homozygous for any HLA locus demonstrated significantly lower PA-specific LP than subjects who were heterozygous at all eight loci (median stimulation indices [SI], 1.84 versus 2.95,
P
= 0.009). Similarly, we found that class I (HLA-A) and class II (HLA-DQA1 and HLA-DQB1) homozygosity was significantly associated with an overall decrease in LP compared with heterozygosity at those three loci. Specifically, individuals who were homozygous at these loci had significantly lower PA-specific LP than subjects heterozygous for HLA-A (median SI, 1.48 versus 2.13,
P
= 0.005), HLA-DQA1 (median SI, 1.75 versus 2.11,
P
= 0.007), and HLA-DQB1 (median SI, 1.48 versus 2.13,
P
= 0.002) loci, respectively. Finally, homozygosity at an increasing number (≥4) of HLA loci was significantly correlated with a reduction in LP response (
P
< 0.001) in a dose-dependent manner. Additional studies are needed to reproduce these findings and determine whether HLA-heterozygous individuals generate stronger cellular immune response to other virulence factors (
Bacillus anthracis
LF and EF) than HLA-homozygous subjects.
The Dot/Icm Effector SdhA Is Necessary for Virulence of Legionella pneumophila in Galleria mellonella and A/J Mice
Authors: Harding Clare R. , Stoneham Charlotte A. , Schuelein Ralf , Newton Hayley , Oates Clare V. , Hartland Elizabeth L. , Schroeder Gunnar N. , Frankel Gad
Published: May 2013

Legionella pneumophila
is an intracellular bacterium that resides within amoebae and macrophages in a specialized compartment termed the
Legionella
-containing vacuole (LCV). As well as providing an intracellular niche for replication, the LCV helps to prevent the release of bacterial components into the cytoplasm. Recognition of these components as danger signals by the host activates immune responses leading to clearance of the bacterium. Here, we examined the role of two important virulence factors of
L. pneumophila
, the potent danger signal flagellin and the translocated Dot/Icm type IVB secretion system effector SdhA, which is crucial to maintain LCV integrity, in the
Galleria mellonella
infection model. We demonstrate that flagellin expression does not contribute to virulence, replication, or induction of clearance mechanisms. Conversely, SdhA expression is important for virulence. We found that in the absence of SdhA, the LCV in hemocytes showed signs of instability and leakage. Furthermore, in contrast to wild-type
L. pneumophila
, a Δ
sdhA
mutant caused a transient depletion of hemocytes and reduced mortality. Analysis of the Δ
sdhA
mutant in the A/J mouse model also showed a significant replication defect. Together, our data underline the crucial importance of SdhA in infection across different model organisms.
Hypoxia-Inducible Factor 1-Regulated Lysyl Oxidase Is Involved in Staphylococcus aureus Abscess Formation
Authors: Beerlage Christiane , Greb Jessica , Kretschmer Dorothee , Assaggaf Mohammad , Trackman Philip C. , Hansmann Martin-Leo , Bonin Michael , Eble Johannes A. , Peschel Andreas , Brüne Bernhard , Kempf Volkhard A. J.
Published: May 2013

Hypoxia-inducible factor 1 (HIF-1) is the key transcription factor involved in the adaptation of mammals to hypoxia and plays a crucial role in cancer angiogenesis. Recent evidence suggests a leading role for HIF-1 in various inflammatory and infectious diseases. Here we describe the role of HIF-1 in
Staphylococcus aureus
infections by investigating the HIF-1-dependent host cell response. For this purpose, transcriptional profiling of HIF-1α-deficient HepG2 and control cells, both infected with
Staphylococcus aureus
, was performed. Four hours after infection, the expression of 190 genes, 24 of which were regulated via HIF-1, was influenced.
LOX
(encoding lysyl oxidase) was one of the upregulated genes with a potential impact on the course of
S. aureus
infection. LOX is an amine oxidase required for biosynthetic cross-linking of extracellular matrix components. LOX was upregulated
in vitro
in different cell cultures infected with
S. aureus
and also
in vivo
, in kidney abscesses of mice intravenously infected with
S. aureus
and in clinical skin samples from patients with
S. aureus
infections. Inhibition of LOX by β-aminopropionitrile (BAPN) did not affect the bacterial load in kidneys or blood but significantly influenced abscess morphology and collagenization. Our data provide evidence for a crucial role of HIF-1-regulated LOX in abscess formation.
Assessment of the Impact of the Kansas IDeA Network of Biomedical Research Excellence Program on Undergraduate Participation in Research
Authors: Chapes Stephen K. , Velasquez Sarah E.
Published: May 2013

The Kansas IDeA Network of Biomedical Research Excellence (K-INBRE) was established in 2001 and is a network of 10 higher-education institutions in Kansas and northern Oklahoma. The program is funded by the Institutional Development Award (IDeA) program of the National Institutes of Health (NIH). As part of the program’s goal to enhance the research infrastructure in Kansas, a training program was developed to encourage undergraduates to participate in biomedical research. From September 2002 to May 2012, the K-INBRE supported 731 students at 10 institutions. Although 16% of student participants in the program are still undergraduates, 323 of our students have gone into biomedical graduate school or medical school programs. Thirty-seven percent of all the completed students have matriculated into graduate programs and 19% of our completed students went to medical school. Moreover, 12% have gone into other health-related professions. One percent of our students who went into medical school programs are in highly prestigious MD/PhD programs. In the fall of 2011, we surveyed participants from the last 10 years about career choices and the impact of the K-INBRE program on those students. Two hundred twenty-four former and current students responded to the survey with a consensus of high impact of the K-INBRE program on student training, career choices, and perceptions about research.
Impact of a service-Learning Project on student success in Allied Health Microbiology course
Authors: Cain Donna M.
Published: May 2013

Education research shows many benefits of involving students in service learning. However, designing service-learning projects for science courses such as microbiology can be problematic. This article describes an effective, easily adapted project design that gets allied-health microbiology students to apply classroom knowledge towards educating the general public about infectious diseases.
Bioremediation Approaches in a Laboratory Activity for the Industrial Biotechnology and Applied Microbiology (IBAM) Course
Authors: Iustman L. Raiger , López N. I. , Ruzal S. M. , Vullo D. L.
Published: May 2013

Industrial Biotechnology and Applied Microbiology is an optional 128h-course for Chemistry and Biology students at the Faculty of Sciences, University of Buenos Aires, Argentina. This course is usually attended by 25 students, working in teams of two. The curriculum, with 8 lab exercises, includes an oil bioremediation practice covering an insight of bioremediation processes: the influence of pollutants on autochthonous microbiota, biodegrader isolation and biosurfactant production for bioavailability understanding. The experimental steps are: (A) evaluation of microbial tolerance to pollutants by constructing pristine soil microcosms contaminated with diesel or xylene and (B) isolation of degraders and biosurfactant production analysis. To check microbial tolerance, microcosms are incubated during one week at 25-28ºC. Samples are collected at 0, 4 and every 48 h for CFU/g soil testing. An initial decrease of total CFU/g related to toxicity is noticed. At the end of the experiment, a recovery of the CFU number is observed, evidencing enrichment in biodegraders. Some colonies from the CFU counting plates are streaked in M9-agar with diesel as sole carbon source. After a week, isolates are inoculated on M9-Broth supplemented with diesel to induce biosurfactant production. Surface tension and Emulsification Index are measured in culture supernatants to visualize tensioactive effect of bacterial products. Besides the improvement in the good microbiological practices, the students show enthusiasm in different aspects, depending on their own interests. While biology students explore and learn new concepts on solubility, emulsions and bioavailability, chemistry students show curiosity in bacterial behavior and manipulation of microorganisms for environmental benefits.
An Incredibly Fun and Easy Way to Learn Clinical MicrobiologyReview of:	Clinical Microbiology Made Ridiculously Simple,	5th ed.;	GladwinMark and	TrattlerWilliam; (	2011).	MedMaster Inc.,	Miami, FL.	400 pages.
Authors: Jandu Narveen , Tawde Mangala
Published: May 2013

Review of:
Clinical Microbiology Made Ridiculously Simple, 5th ed.;
Mark Gladwin and William Trattler; (2011). MedMaster Inc., Miami, FL. 400 pages.
The Newest Educational and Engaging On-Line Resources for Students and Instructors from
National Geographic Education
Authors: Hill Kendra M.
Published: May 2013

Review of:
National Geographic Education
– Online Teaching Resources
JMBE
Supports 20 Years of Teaching Excellence at ASMCUE and Offers ASM Laboratory Safety Guidelines
Authors: Woolverton Christopher J.
Published: May 2013

Since 2010,
JMBE
has included the abstracts from the ASM Conference for Undergraduate Educators (ASMCUE), providing authors a citation for their work in biology education. This year ASM celebrates the 20th anniversary of the ASMCUE, so congratulations to the abstract authors published in this issue for being a part of this significant milestone. Also of note is the Biosafety Guidelines for Teaching Laboratories, authored by Elizabeth A. B. Emmert and the ASM Task Committee on Laboratory Biosafety. Two enhancements to ensure the long-term sustainability of the journal were introduced with this issue: easy to follow training videos that complement the printed guidelines for authors and reviewers, and opportunities for print and online advertising.
Alternative routes in road networks
Authors: Abraham Ittai , Delling Daniel , Goldberg Andrew V. , Werneck Renato F.
Published: May 2013

We study the problem of finding good alternative routes in road networks. We look for routes that are substantially different from the shortest path, have small stretch, and are locally optimal. We formally define the problem of finding alternative routes with a single via vertex, develop efficient algorithms for it, and evaluate them experimentally. Our algorithms are efficient enough for practical use and compare favorably with previous methods in both speed and solution quality.
Self-Alignment Schemes for the Implementation of Addition-Related Floating-Point Operators
Authors: Ould-Bachir Tarek , David Jean Pierre
Published: May 2013

Advances in semiconductor technology brings to the market incredibly dense devices, capable of handling tens to hundreds floating-point operators on a single chip; so do the latest field programmable gate arrays (FPGAs). In order to alleviate the complexity of resorting to these devices in computationally intensive applications, this article proposes hardware schemes for the realization of addition-related floating-point operators based on the self-alignment technique (SAT). The article demonstrates that the schemes guarantee an accuracy as if summation was computed accurately in the precision of operator’s internal mantissa, then faithfully rounded to working precision. To achieve such performance, the article adopts the redundant high radix carry-save (HRCS) format for the rapid addition of wide mantissas. Implementation results show that combining the SAT and the HRCS format allows the implementation of complex operators with reduced area and latency, more so when a fused-path approach is adopted. The article also proposes a new hardware operator for performing endomorphic HRCS additions and presents a new technique for speeding up the conversion from the redundant HRCS to a conventional binary format.