bluuebunny/crossref_metadata_2025 huggingface dataset:
Can stress-timing and syllable-timing be perceived?
Authors: Arvaniti Amalia
Published: October 2010

The listeners’ ability to classify languages as stress- or syllable-timed was indirectly tested in two experiments. In the first, American, Greek, and Korean listeners rated low-pass filtered utterances of English, German, Greek, Italian, Korean, and Spanish for similarity to a series of non-speech trochees, using a 7-point scale. In a second experiment (with English listeners), low-pass filtering was replaced by “sasasa” (in which consonantal intervals are replaced by [s] and vocalic intervals by [a]); stimuli either retained their original F0 or had flat F0. Stress-timed English and German were expected to be rated more similar to the trochee series, since their rhythm is based on the alternation of stressed and unstressed syllables and is thus akin to trochees; low ratings were expected for syllable-timed Spanish and Italian, and intermediate ratings for (unclassified) Korean and Greek. Ratings did not support rhythm class distinctions: English was rated least trochee-like by all listener groups, and the other five languages were rated similarly to each other. Further, intonation played a more important role in classification than previously expected. Overall, the results cast doubt on the impressionistic basis of rhythm classes and more generally on the idea that speech rhythm can be equated with timing.
The role of tempo and pitch in rhythm class discrimination.
Authors: Boswell Tara , Arvaniti Amalia
Published: October 2010

According to the well-known rhythm typology, languages are stress-, syllable-, and mora-timed, a distinction said to be supported by AAX (oddball) experiments in which listeners fail to discriminate between languages of the same rhythm class. However, results show that in some such cases discrimination is possible (e.g., between Polish and English), suggesting that factors other than timing may play a part. Here the hypothesis that tempo and pitch drive discrimination was tested. English was the context language (AA) to which Spanish, Korean, and Danish (X) were compared. The consonantal intervals of the original sentences were replaced by [s] and the vocalic intervals by [a]. Interval relative timing was held constant; tempo was either that of the original utterances or replaced by the average from all stimuli. For each tempo condition, pitch was either flat or a synthesized version of each utterance’s original F0. Original F0 greatly facilitated discrimination, while flat F0 and average tempo hindered discrimination both within and across rhythm classes. These results suggest that it is not rhythm class that drives discrimination in AAX experiments, thereby adding to a body of research findings showing no strong evidence for rhythm classes either in production or in perception.
Mean and variance of energy flux expressions for intensity in uncertain waveguides.
Authors: LePage Kevin D.
Published: October 2010

Energy flux methods have proven to provide a powerful method for rapidly and accurately computing transmission loss, impulse responses, target scattering, and reverberation in shallow water environments. At the NATO Undersea Research Centre, tools have been developed which rely on the accuracy and speed of the energy flux approach to compute measures of multistatic system performance. In support of the extension of the capabilities of these tools, expressions for the mean and variance of the intensity of acoustic propagation using energy flux concepts have been derived for uncertainty in the bottom reflection coefficient, sound speed profile, and bathymetry. These expressions provide a compliment to the use of Monte Carlo techniques for the evaluation of the expected level of performance of multistatic systems. The accuracy of the expressions is evaluated by comparison to Monte Carlo estimates of the quantities of interest.
Transport theory for range dependent environments.
Authors: Thorsos Eric I. , Elam W. T. , Henyey Frank S. , Yang Jie , Reynolds Stephen A.
Published: October 2010

Transport theory has been developed for modeling shallow water propagation at mid frequencies (1–10 kHz) where forward scattering from a rough sea surface is taken into account in a computationally efficient manner. The method is based on a decomposition of the field in terms of unperturbed modes, and forward scattering at the sea surface leads to mode coupling that is treated with perturbation theory. Aside from the rough sea surface, the environment has previously been taken as range independent. In order to extend the applicability of this approach, range dependence is now considered in the form of a varying bottom depth. The conditions under which adiabatic modes can be incorporated into transport theory to account for slow deterministic variation in the waveguide depth have been investigated and will be described. Rough surface PE simulations are used to provide ground truth for the transport theory method. [Work supported by ONR Ocean Acoustics.]
Scintillation statistics of broadband acoustic transmissions in the Gulf of Maine.
Authors: Tran Duong D. , Andrews Mark , Gong Zheng , Chauhan Hari , Makris Nicholas , Ratilal Purnima
Published: October 2010

Broadband acoustic transmissions from a vertical source array in the 300–1200 Hz frequency range of 1 s duration, with source-receiver separations ranging from 2 to 20 km measured in the Gulf of Maine, are analyzed. The received signal intensity is shown to follow the gamma distribution, implying that the field has been fully saturated by independent multimodal propagation contributions. The gamma distribution depends on the mean intensity and the number of independent statistical fluctuations of the received signal. The standard deviations of the received broadband signal intensities are found to be a function of center frequencies and bandwidths. For a fixed center frequency, the standard deviation decreases with increasing bandwidth, implying that there are more independent fluctuations in larger bandwidth signals. The measured scintillation statistics are verified with a range-dependent numerical Monte-Carlo propagation model incorporating linear internal wave fluctuations in the random waveguide. Further analysis with the model indicates the range-dependence of broadband signal intensity standard deviations, which increase rapidly from deterministic at the source location to a maximum at roughly 3-km range and decay gradually afterward. The standard deviation of a short-duration monotonic signal remains constant at between 5 and 6 dB after a 3-km range since it contains only one independent fluctuation.
Influence of seabed geoacoustics on in-water sound levels produced by a small airgun array.
Authors: Warner Graham A.
Published: October 2010

Underwater sound from a small airgun array was measured at two locations 170 km apart in the Chukchi Sea, Alaska, in water depths of 41 and 48 m. The sounds were measured at distances from the array ranging from 200 m to 20 km using two seabed-mounted calibrated recording systems. Even though the airgun array, acoustic recording equipment, and operational geometries at the two sites were the same, the sound levels were substantially different between the sites. Analysis of the pressure waveforms showed that the difference was caused by differing seabed reflectivities. An analysis of headwave arrivals showed a high-speed layer close to the seabed at the more reflective site. This layer produced strong acoustic reflections that resulted in the higher in-water sound levels measured. The finding suggests that bottom geoacoustic changes over relatively small distances can lead to a substantial variation in underwater sound levels near seismic surveys in shallow water.
A simple method to optimize the sound package in a double wall structure.
Authors: Doutres Olivier , Atalla Noureddine
Published: October 2010

The acoustic contributions to the transmission loss of an unbounded sound package in a double panel structure are investigated. For this purpose, a simple analytic expression of the normal incidence sound transmission loss of the double panel structure is proposed in terms of three main contributions: sound transmission loss of the panels, sound transmission loss of the blanket, and sound absorption due to multiple reflections inside the structure. It is shown that (i) at high frequencies, the transmission loss contribution of the blanket is preponderant compared to the absorption contributions;(ii) at the cavity resonance frequencies, the absorption contribution allows to attenuate the dips of insulation; and (iii) at medium and low frequencies, when the absorption performance of the porous layer is poor, the absorption contributions in the air-gaps can decrease the sound transmission loss performance of the double panel. The proposed methodology can also be used to estimate, from classical impedance tube measurements of the sound package only, the transmission loss of the whole double wall configuration. Testing the influence of various sound packages in a given double panel structure thus becomes quick and much less expensive compared to classical tests.
Three-dimensional Bayesian passive acoustic tracking of walruses in the Chukchi Sea.
Authors: Rideout Brendan P. , Dosso Stan E. , Hannay David E.
Published: October 2010

A Bayesian travel-time inversion method was developed for 3-D localization and tracking using multipath arrival times of knock-type sounds produced by walruses. The method accounts for data errors and uncertainties in environmental and geometric parameters. Data were collected on three seafloor sound recorders, arranged in an equilateral triangle with approximately 500-m sides, deployed in 30 m of water in the Chukchi Sea near the Hanna Shoal, west of Barrow, Alaska. Pacific Walrus (Odobenus rosmarus divergens) calls were recorded by these recorders for 2.5 months in the summer of 2009. A regularized, linearized inversion algorithm was used to estimate 3-D tracks and track uncertainties for these calling walruses. Regularization incorporates prior information (expected values and uncertainty estimates) for the recorder locations and acoustic environment (water depth and sound speed) as well as preferred track characteristics. Inverting for the smoothest (simplest) track consistent with the acoustic data and prior information mitigates the risk of over-interpreting track structure due to data errors and environmental and geometric uncertainties. Hence, this approach provides more plausible sequences of source positions than a non-regularized solution. Tracks for walrus dives from the 2009 dataset will be presented.
Short term phonetic and phonological changes during Spanish instruction.
Authors: Viswanathan Navin , Losow Janna M. , Fabiano-Smith Leah , Olmstead Anne J.
Published: October 2010

Several studies have shown that phonetic and phonological categories of both languages interact in bilingual speakers [e.g., speech learning model; Flege (1995)]. Interestingly, these categories continuously change over a period of time, drifting toward the characteristics of the ambient language. [Sancier and Fowler (1997)]. In this study, we studied how categories change in a short term bilingual interaction. Specifically, we were interested in whether cross linguistic influences were moderated by the extent of concurrent use of the two languages as well as the linguistic abilities of the target audience. To examine these questions, we recorded the production of Spanish language instructors. Their productions were studied before, during, and after a classroom interaction to determine changes in production. Furthermore, these productions were recorded in Spanish language courses of varying levels to determine specifically whether there was an increased influence of Spanish phonology on English productions in higher-level courses. The speech samples were phonetically transcribed and analyzed. Acoustic analyzes were performed to detect changes in voice onset time [Lisker and Abramson (1964)], vowel space, consonant manner class, and stress patterns. This study has implications for theories of bilingual speech production as well as for second language instruction and education.
Examining the role of talker-specific details in bilingual listeners’ perception of spoken words.
Authors: McLennan Conor T. , Wilson Maura L. , González Julio
Published: October 2010

Previous studies demonstrate that listeners are faster to recognize words recently spoken by the same talker, relative to a different talker. However, there is evidence that such talker effects are more robust when processing is relatively slow. The purpose of the present study was to examine talker effects in bilingual listeners as a function of whether the listeners were hearing words in their first (L1) or second (L2) language. More specifically, in the present study, conducted in Spanish, we examined whether talker changes would affect bilinguals differently, depending on whether Spanish was their L1 (Spanish-English bilinguals) or their L2 (English-Spanish bilinguals). Given that bilinguals typically process their L2 more slowly than their L1, the results were expected to reveal greater talker effects in English-Spanish than in Spanish-English bilinguals. The present study should provide a greater understanding of the role that talker variability plays in bilingual listeners’ online perception of spoken words.
Effects of age of immersion, task demand, and word type on word-recognition response times by native and non-native English-speaking listeners.
Authors: Doty Astrid Z. , Rogers Catherine L. , Bryant Judith B.
Published: October 2010

Although listeners can adapt to many challenging listening conditions, often with little apparent effect on recognition accuracy, speed of processing may also affect an individual’s ability to cope with such challenges in everyday contexts. Native and non-native listeners with either earlier (age 10 or earlier) or later (age 14 or later) ages of immersion in an English-speaking environment heard six lists of 24 words, each composed of 12 lexically easy target words (high-frequency words from sparse, low-frequency phonological neighborhoods) and 12 lexically hard target words (low-frequency words from dense, high-frequency phonological neighborhoods) in an open-set word-identification task. Word lists were presented in quiet, in a moderate degree of background noise, and with or without a competing digit-recall task. In the digit-recall task, listeners saw three or six digits on the monitor prior to presentation of the word list and were asked to recall the digits at the end of the word-recognition task. While there was no effect of the added digit-recall task on word-recognition accuracy, response times for correctly identified items were significantly longer for the digit-recall condition, for the later learners of English only. Group and word type effects on response times will also be addressed.
Non-native speech segmentation of a prosodically dissimilar language.
Authors: Adams Tuuli M.
Published: October 2010

Native English listeners completed different combinations of the following tasks: learning words of Japanese, listening to fluent speech in Japanese, and identifying possible words of Japanese. Participants identified possible words from pairs of correctly and incorrectly segmented syllable sequences occurring in the fluent speech. Results indicate that listeners in the word-learning conditions were better at identifying possible words than those who only listened to fluent speech. Since English listeners are hypothesized to use a stress-based speech segmentation strategy, the presence of lexical pitch accents, but lack of stress, in Japanese may have lead to a mismatch between the phonetic cues that signal word boundaries in the non-native and native languages. Therefore, participants did not gain as much advantage from listening and attempting to segment fluent speech in Japanese as they have been shown to for a language metrically similar to English, like Finnish [Adams (2010)]. However, a combination of word-learning and fluent speech listening did lead to more consistent performance across subjects on the word identification task, indicating that listening to fluent speech may still aid in the perception of certain phonetic cues associated with the well-formedness of words in the non-native language.
The relationship between vowel identification in noise and vowel intelligibility for Chinese and Korean speakers.
Authors: Jin Su-Hyun , Liu Chang , Moon Somang
Published: October 2010

The present study aims to investigate the effects of background noise on English vowel perception for non-native listeners and to examine the relationship between vowel perception and vowel intelligibility for non-native people. For experiment 1, vowel identification was measured in two noise types: multi-talker babble and long-term speech shaped noise at various signal-to-noise ratios (SNRs) for English-native (EN), Chinese-native (CN), and Korean-native (KN) listeners. For experiment 2, English vowels spoken by CN and KN speakers who served as listeners in experiment 1 were recorded. Preliminary data of vowel perception showed that at low SNRs (−18 to −15 dB SNR), all three groups of listeners performed poorly, and at relatively middle and high SNRs, vowel identification for both CN and KN listeners was significantly poorer than EN listeners. Even at +3 dB SNR, the average identification scores for non-native listeners were more than 20% less than those for EN listeners. Furthermore, there was significant individual variability in vowel identification within each non-native group. This variability in vowel perception might be related with variability in vowel intelligibility for the non-native individuals. Vowel intelligibility for the non-native speakers will be evaluated by EN listeners. The implication on bilingual speech perception and production will be discussed.
Perception of Canadian French word-final vowels in lexical and morphosyntactic minimal pairs by English learners of French.
Authors: Law Franzo , Strange Winifred
Published: October 2010

The present study investigated perception of Canadian French word-final vowels in various phonetic contexts by English-dominant bilinguals living in Montreal. In a modified identification task, listeners selected responses that rhymed with the target words; production of each response corresponded to a target vowel (e.g., response “ai” is pronounced /e/). Target words included real and nonsense words contrasting in word-final /i e ε a o u y o// and morphosyntactic verb minimal pairs contrasting in word-final /e-ε/ (e.g., first-person singular future “parlerai” versus conditional “parlerais”) embedded in carrier sentences. Of interest were the perception patterns of /e/ and /ε/. Both are phontactically allowed word-final in Canadian French, but not in English. Also, previous studies suggest that /y/ and /u/ could have context-dependent perceptual patterns for English listeners. Results showed that bilingual listeners performed well overall and were at ceiling for control vowels. Most mistakes were /e-ε/ confusions, though participants were above chance, with highly proficient French bilinguals making fewer errors. /y/ and /u/ were accurately identified across contexts, suggesting that /y/ and /u/ perception was not particularly difficult in this study. Reaction time differences, mouse tracking patterns, and effects of real versus nonsense words will also be discussed. [Work supported by NIH F31DC008075.]
The production of English front vowels by Spanish speakers: A study of vowel duration based on vowel tenseness and consonant voicing.
Authors: Todt Kirsten R.
Published: October 2010

In many languages, vowels preceding voiced consonants have longer duration than vowels preceding voiceless consonants. Previous studies have suggested that while this difference may be considered a phonetic rule in many languages including Spanish, it constitutes a phonological rule in English. Additionally, vowel duration is used phonologically in English to distinguish tense and lax vowels. Furthermore, these two phonological rules interact. Thus, Spanish speakers learning English must acquire two phonological rules of vowel duration and the interaction between the rules. The purpose of this study is to examine the acquisition of these phonological rules and interactions by Spanish speakers by comparing the productions of native English speakers and native Spanish speakers. Both groups of subjects produced English stimulus words that contrasted tense and lax vowels and consonant voicing, as well as syllable structure. The analysis of durational patterns by native English speakers provides data about the interaction of the phonological rules in production. The analysis of the Spanish data may have implications for second language phonology, particularly the interaction of universal phonetic rules and language-specific phonological rules.
The effect of age of acquisition and second-language experience on prosody and segments: A cross-sectional study of Korean bilinguals’ English and Korean production.
Authors: Oh Grace E. , Guion-Anderson Susan
Published: October 2010

The effect of age of acquisition and amount of experience on the segmental and prosodic production of the first-(L1) and second-language (L2) was investigated. Forty Korean learners of English varying in age (adult versus child) and amount of experience (6 months versus 6 years) as well as 20 age-matched native English speaking adults and children participated. In the segmental domain, spectral quality and duration of eight English and seven Korean vowels were compared. In order to examine prosodic aspects of production, English words containing stressed and unstressed syllables and Korean four-syllable phrases were elicited. Results for adult groups revealed that the production of Korean vowels, but not English vowels, was influenced by the L2 experience, indicating plasticity in the L1. For prosody, small effects of experience on English production were found. As for the children, production of both English and Korean vowels and prosody varied by group. The 6-year-experience child group was native-like in English vowels but not in unstressed syllables. The results suggest that there is a dynamic interaction between L1 and L2 in segments as well as in prosody.
Acquisiton of segments and intonation by English learners of Korean.
Authors: Kim Yun Jung , Oh Mira
Published: October 2010

Many studies have demonstrated mutual influences between first (L1) and second (L2) languages. However, while much research examined L1 and L2 pairs that match in the number of contrasts [Flege (1991); MacKay et al. (2001); Harada (2003)], little research has been done on languages with different numbers of laryngeal contrasts in stops. Furthermore, not much research has been done on L1 and L2 influences on learning prosody. This study aims to investigate how English (a stressed-timed language that has a two-way stop contrast) learners of Korean acquire Korean (a syllable-timed language that has a three-way stop contrast) stops and intonation. Three groups of English learners of Korean (beginning, intermediate, advanced; four participants in each group) will be compared with native Korean speakers with respect to acoustic realizations of stops and intonation. VOT, the duration of vowels adjacent to stops and f0 of vowel onset will be measured for stops. As for intonation, AP-initial and -final tone realizations of English learners of Korean will be compared with those of Korean speakers. It will be shown that duration cues, such as VOT, are acquired earlier than pitch. The implication of the results in Korean education will also be discussed.
Learning novel phonetic categories in perception and production.
Authors: Baese-Berk Melissa M.
Published: October 2010

Much is known about perceptual category formation in both first and second languages. For example, researchers have demonstrated that in the laboratory listeners are able to form novel perceptual categories after a short period of exposure [e.g., Hayes (2003); Maye & Gerken (2000); Maye & Gerken (2001)]. However, little research has examined how perceptual category formation proceeds in production or how training in one modality affects learning in the other modality. This study systematically manipulates training modality while testing participants in both perception and production. Participants were trained on a novel phonetic category contrast using an implicit learning paradigm [Maye & Gerken (2000); Maye & Gerken (2001)]. Across participants, training either consisted of perception-only, in which participants did not explicitly produce tokens, or perception+production, in which participants were instructed to explicitly repeat tokens. Participants were tested on their ability to perceive and produce the new contrast before and after training. Perception results demonstrate that the perception-only training group learns to discriminate the trained contrast. The perception+production training group discriminates less well, suggesting that production training can disrupt perceptual learning. Results of this study will increase understanding of how category formation occurs in both modalities and give insight into the relationship between perception and production.
Acoustical Society of America Pioneers of Underwater Acoustics Medal
Authors: Frisk George V.
Published: October 2010

The Pioneers of Underwater Acoustics Medal is presented to an individual irrespective of nationality, age, or society affiliation, who has made an outstanding contribution to the science of underwater acoustics, as evidenced by publication of research in professional journals or by other accomplishments in the field. The award was named in honor of five pioneers in the field: H. J. W. Fay, R. A. Fessenden, H. C. Hayes, G. W. Pierce, and P. Langevin.
Single-Cell Analysis Reveals That Insulation Maintains Signaling Specificity Between Two Yeast MAPK Pathways with Common Components
Authors: Patterson Jesse C. , Klimenko Evguenia S. , Thorner Jeremy
Published: October 2010

Yeast cells can respond simultaneously to pheromone and hyperosmotic stress.
Prions Speed Muscle Repair
Authors: Gough Nancy R.
Published: October 2010

Mice genetically deficient in prion protein (PrP
C
) exhibit slower muscle regeneration after injury.
Assisting Arrest
Authors: VanHook Annalisa M.
Published: October 2010

Natriuretic peptide signaling maintains meiotic arrest in oocytes.
Enhancing Activity from the Inside
Authors: Gough Nancy R.
Published: October 2010

Cytoplasmic cytohesins promote the active conformation of ligand-bound epidermal growth factor receptors.
Inflammation Response in Living Color
Authors: Mueller Kristen L.
Published: October 2010

In vivo dynamic imaging reveals the underlying mechanisms of recruitment of neutrophils into injured tissue.
Time and Temperature
Authors: Kiberstis Paula A.
Published: October 2010

The master pacemaker in the mammalian brain resists the resetting effect of temperature to provide a universal entraining signal.
BDNF, Dopamine, and Cocaine Reward
Authors: Stern Peter R.
Published: October 2010

Selective manipulation of neuron subtypes produces opposite effects on behavioral responses to cocaine.
Population Pharmacokinetics of Nevirapine in HIV-1-Infected Pregnant Women and Their Neonates
Authors: Benaboud Sihem , Ekouévi Didier K. , Urien Saik , Rey Elisabeth , Arrivé Elise , Blanche Stéphane , Gray Glenda , Sim Kruy Leang , Avit Divine , McIntyre James , Nerrienet Eric , Dabis François , Tréluyer Jean-Marc , Hirt Déborah
Published: October 2010

The aim of the present study was to describe the nevirapine (NVP) pharmacokinetics (PK) in pregnant women and their neonates and to evaluate the transplacental drug transfer and administration scheme for the prevention of mother-to-child transmission. Thirty-eight HIV-1-infected pregnant women were administered one tablet of NVP (200 mg) and two tablets of tenofovir-emtricitabine (Truvada) at the initiation of labor. Children were given NVP syrup (2 mg/kg of body weight) as a single dose (sdNVP) on the first day of life. By pair, NVP concentrations were measured in 11 maternal, 1 cord blood, and 2 neonatal plasma samples and analyzed by a population approach. A one-compartment model was used for mothers and neonates; the absorption rate constants for mothers and neonates were 0.95 h−1(intersubject variability, 111%) and 0.39 h−1, respectively; the apparent elimination clearances were 1.42 liter·h−1(intersubject variability, 22%) and 0.035 liter·h−1, respectively; and apparent volumes of distribution were 87.3 liters (intersubject variability, 25%) and 5.65 liters, respectively. An effect compartment was linked to maternal circulation by mother-to-cord and cord-to-mother rate constants of 1.10 h−1and 1.43 h−1, respectively. Placental transfer, expressed as the fetal-to-maternal area under the curve ratio, was 75%. Neonates had a very long half-lives (110 h) compared to adults. In the 38 mothers, the simulated median individual predicted time during which the NVP concentration remained above the half-maximal inhibitory concentration (IC50) was 13.2 days (range, 12 to 19.2 days). Thus, the administration of tenofovir-emtricitabine for at least 3 weeks after delivery should be considered to prevent the emergence of resistant viruses. The neonate must receive sdNVP immediately after birth when the infant is born less than 30 min after maternal drug intake to keep NVP concentrations above the IC50.
Tracking Origins and Spread of Sulfadoxine-Resistant
Plasmodium falciparum dhps
Alleles in Thailand
Authors: Alam Md Tauqeer , Vinayak Sumiti , Congpuong Kanungnit , Wongsrichanalai Chansuda , Satimai Wichai , Slutsker Laurence , Escalante Ananias A. , Barnwell John W. , Udhayakumar Venkatachalam
Published: October 2010

The emergence and spread of drug-resistant
Plasmodium falciparum
have been a major impediment for the control of malaria worldwide. Earlier studies have shown that similar to chloroquine (CQ) resistance, high levels of pyrimethamine resistance in
P. falciparum
originated independently 4 to 5 times globally, including one origin at the Thailand-Cambodia border. In this study we describe the origins and spread of sulfadoxine-resistance-conferring dihydropteroate synthase (
dhps
) alleles in Thailand. The
dhps
mutations and flanking microsatellite loci were genotyped for
P. falciparum
isolates collected from 11 Thai provinces along the Burma, Cambodia, and Malaysia borders. Results indicated that resistant
dhps
alleles were fixed in Thailand, predominantly being the S
GEG
A,
AGE
AA, and S
GNG
A triple mutants and the
AG
KAA double mutant (mutated codons are underlined). These alleles had different geographical distributions. The S
GEG
A alleles were found mostly at the Burma border, while the S
GNG
A alleles occurred mainly at the Cambodia border and nearby provinces. Microsatellite data suggested that there were two major genetic lineages of the triple mutants in Thailand, one common for S
GEG
A/S
GNG
A alleles and another one independent for
AGE
AA. Importantly, the newly reported S
GNG
A alleles possibly originated at the Thailand-Cambodia border. All parasites in the Yala province (Malaysia border) had
AG
KAA alleles with almost identical flanking microsatellites haplotypes. They were also identical at putatively neutral loci on chromosomes 2 and 3, suggesting a clonal nature of the parasite population in Yala. In summary, this study suggests multiple and independent origins of resistant
dhps
alleles in Thailand.
Carbapenem-Hydrolyzing GES-Type Extended-Spectrum β-Lactamase in
Acinetobacter baumannii
Authors: Bonnin Rémy A. , Nordmann Patrice , Potron Anaïs , Lecuyer Hervé , Zahar Jean-Ralph , Poirel Laurent
Published: October 2010

Acinetobacter baumannii
isolate AP was recovered from a bronchial lavage of a patient hospitalized in Paris, France.
A. baumannii
AP was resistant to all β-lactams, including carbapenems, and produced the extended-spectrum β-lactamase (ESBL) GES-14, which differs from GES-1 by two substitutions, Gly170Ser and Gly243Ala. Cloning of the
bla
GES-14
gene followed by its expression in
Escherichia coli
showed that GES-14 compromised significantly the efficacy of all β-lactams, including cephalosporins, aztreonam, and carbapenems. The carbapenemase activity of purified GES-14 was confirmed by kinetic studies. The
bla
GES-14
gene was located into a class 1 integron structure and located onto a ca. 95-kb self-transferable plasmid. This study identified a very broad-spectrum β-lactamase in
A. baumannii
.
Activity of Deferasirox in
Mucorales
: Influences of Species and Exogenous Iron
Authors: Lewis Russell E. , Pongas Georgios N. , Albert Nathaniel , Ben-Ami Ronen , Walsh Thomas J. , Kontoyiannis Dimitrios P.
Published: October 2010

Differences in deferasirox susceptibility among members of the order
Mucorales
are unknown. Here we show that
Cunninghamella
bertholletiae
(four isolates) and
Mucor
species (five isolates) display higher deferasirox MICs and minimal fungicidal concentrations compared to
Rhizopus
species (six isolates). Exogenous iron further attenuated the deferasirox susceptibility of
Mucorales
isolates with low MICs. Vital staining revealed damage to subapical compartments in susceptible strains.
Failure of Vancomycin Continuous Infusion against Experimental Endocarditis Due to Vancomycin-Intermediate
Staphylococcus aureus
Authors: Entenza J. M. , Veloso T. R. , Vouillamoz J. , Giddey M. , Moreillon P.
Published: October 2010

Continuous infusion of vancomycin was evaluated against experimental endocarditis due to heterogeneous vancomycin-intermediate
Staphylococcus aureus
(hVISA) and VISA. Animals were infected with hVISA PC1 (vancomycin MIC, 2 mg/liter) or VISA PC3 (vancomycin MIC, 8 mg/liter) and treated for 5 days with constant serum levels of 20 or 40 mg/liter. Vancomycin continuous infusion was unsuccessful, as 20 mg/liter was barely active against PC1 (6 of 13 sterile vegetations) and 40 mg/liter failed against PC3 (2 of 9 sterile vegetations).
Sequence of pR3521, an IncB Plasmid fromEscherichia coliEncoding ACC-4, SCO-1, and TEM-1 β-Lactamases
Authors: Papagiannitsis C. C. , Tzouvelekis L. S. , Kotsakis S. D. , Tzelepi E. , Miriagou V.
Published: October 2010

The sequence of pR3521, a self-transmissible plasmid fromEscherichia coli, was determined. pR3521 (110,416 bp) comprised a contiguous IncB sequence (84,034 bp) sharing extensive similarities with IncI replicons and an acquired region (26,382 bp) carrying sequences of diverse origin, containingblaACC-4,blaSCO-1,blaTEM-1b(two copies),strA,strB,sul2, andaacC2.
Molecular Characterization of Fluoroquinolone Resistance inMycobacterium tuberculosis: Functional Analysis ofgyrAMutation at Position 74
Authors: Lau Ricky W. T. , Ho Pak-Leung , Kao Richard Y. T. , Yew Wing-Wai , Lau Terrence C. K. , Cheng Vincent C. C. , Yuen Kwok-Yung , Tsui Stephen K. W. , Chen Xinchun , Yam Wing-Cheong
Published: October 2010

A PCR-sequencing assay was evaluated for direct detection of mutations in the quinolone resistance-determining region (QRDR) of gyrase A (gyrA) gene in fluoroquinolone-resistantMycobacterium tuberculosisin respiratory specimens. As determined bygyrAQRDR analysis, complete concordance of genotypic and phenotypic fluoroquinolone resistance was demonstrated. Our results indicate that the assay is a rapid and reliable method for the diagnosis of fluoroquinolone-resistant tuberculosis, facilitating timely clinical management and public health control. Using the assay, we detected a novelgyrAAla74Ser mutation inM. tuberculosisdirectly from sputum specimens. The functional effect of the Ala74Ser mutant was verified through the study of the DNA supercoiling inhibitory activity of fluoroquinolones against the recombinant gyrase. The drug-mediated gyrase-DNA cleavage complex model suggests perturbation of thegyrA-gyrAdimer interface caused by the Ala74Ser mutation probably disturbs the putative quinolone binding pocket and leads to the reduction of the drug binding affinity. A number ofgyrAmutations (Glu21Gln, Ser95Thr, and Gly668Asp) were also characterized to be natural polymorphisms not associated with fluoroquinolone resistance.
Flow Cytometry as a Tool To Determine the Effects of Cell Wall-Active Antibiotics on Vancomycin-Susceptible and -Resistant
Enterococcus faecalis
Strains
Authors: Chau Françoise , Lefort Agnès , Benadda Samira , Dubée Vincent , Fantin Bruno
Published: October 2010

Flow cytometry and confocal microscopy were used to study the effects of vancomycin, daptomycin, telavancin, and PA1409, a new investigational vancomyquine, on the morphology, membrane potential, and permeability of glycopeptide-susceptible and -resistant
Enterococcus faecalis
strains. Daptomycin exerted the most pronounced effects on bacterial size and bacterial permeability against susceptible and resistant strains.
Prevalence and Mechanism of Resistance to Antimicrobial Agents in Group G Streptococcal Isolates from China
Authors: Yin Jun , Yu Sangjie , Liu Xiaorong , Li Ye , Gao Wei , Ma Xiang , Yang Yonghong
Published: October 2010

Eighty group G streptococcal stains were collected from Chinese children. Susceptibility testing was done by a double-dilution and a disk diffusion method. PCR was used to test drug-resistant genes, and the χ2test and definite probability methods were used to test for statistically significant differences among the three groups. Thirty-four isolates (42.5%) showed resistance to erythromycin. There are differences between the resistance characteristics of group G streptococci from different regions of China.
Cross-Resistance Profile Determination of Two Second-Generation HIV-1 Integrase Inhibitors Using a Panel of Recombinant Viruses Derived from Raltegravir-Treated Clinical Isolates
Authors: Van Wesenbeeck L. , Rondelez E. , Feyaerts M. , Verheyen A. , Van der Borght K. , Smits V. , Cleybergh C. , De Wolf H. , Van Baelen K. , Stuyver L. J.
Published: October 2010

The integrase inhibitor raltegravir (RAL) is currently used for the treatment of both treatment-naïve and treatment-experienced HIV-1-infected patients. Elvitegravir (EVG) is in late phases of clinical development. Since significant cross-resistance between RAL and EVG is observed, there is a need for second-generation integrase inhibitors (INIs) with a higher genetic barrier and limited cross-resistance to RAL/EVG. A panel of HIV-1 integrase recombinants, derived from plasma samples from raltegravir-treated patients (baseline and follow-up samples), were used to study the cross-resistance profile of two second-generation integrase inhibitors, MK-2048 and compound G. Samples with Q148H/R mutations had elevated fold change values with all compounds tested. Although samples with the Y143R/C mutation had reduced susceptibility to RAL, they remained susceptible to MK-2048 and compound G. Samples with the N155H mutation had no reduced susceptibility to compound G. In conclusion, our results allowed ranking of the INIs on the basis of the antiviral activities using recombinant virus stocks from RAL-treated patient viruses. The order according to decreasing susceptibility is compound G, MK-2048, and EVG.
A Kunitz Protease Inhibitor from
Dermacentor variabilis
, a Vector for Spotted Fever Group Rickettsiae, Limits
Rickettsia montanensis
Invasion
Authors: Ceraul Shane M. , Chung Ashley , Sears Khandra T. , Popov Vsevolod L. , Beier-Sexton Magda , Rahman M. Sayeedur , Azad Abdu F.
Published: October 2010

A defining facet of tick-
Rickettsia
symbioses is the molecular strategy employed by each partner to ensure its own survival. Ticks must control rickettsial colonization to avoid immediate death. In the current study, we show that rickettsial abundance in the tick midgut increases once the expression of a Kunitz-type serine protease inhibitor from the American dog tick (
Dermacentor variabilis
) (DvKPI) is suppressed by small interfering RNA (siRNA). A series of
in vitro
invasion assays suggested that DvKPI limits rickettsial colonization during host cell entry. Interestingly, we observed that DvKPI associates with rickettsiae
in vitro
as well as in the tick midgut. Collectively, our data demonstrate that DvKPI limits host cell invasion by
Rickettsia montanensis
, possibly through an association with the bacterium.
Meningococcal Internalization into Human Endothelial and Epithelial Cells Is Triggered by the Influx of Extracellular
l
-Glutamate via GltT
l
-Glutamate ABC Transporter in
Neisseria meningitidis
Authors: Takahashi Hideyuki , Kim Kwang Sik , Watanabe Haruo
Published: October 2010

Meningococcal internalization into human cells is likely to be a consequence of meningococcal adhesion to human epithelial and endothelial cells. Here, we identified three transposon mutants of
Neisseria meningitidis
that were primarily defective in the internalization of human brain microvascular endothelial cells (HBMEC), with insertions occurring in the
gltT
(a sodium-independent
l
-glutamate transporter) gene or its neighboring gene,
NMB1964
(unknown function). NMB1964 was tentatively named
gltM
in this study because of the presence of a mammalian cell entry (MCE)-related domain in the deduced amino acid sequences. The null Δ
gltT-
Δ
gltM N. meningitidis
mutant was also defective in the internalization into human umbilical vein endothelial cells and the human lung carcinoma epithelial cell line A549, and the defect was suppressed by transcomplementation of the mutants with
gltT

+

-gltM

+

genes. The intracellular survival of the Δ
gltT-
Δ
gltM
mutant in HBMEC was not largely different from that of the wild-type strain under our experimental conditions. Introduction of a1-bp deletion and amber or ochre mutations in
gltT-gltM
genes resulted in the loss of efficient internalization into HBMEC. The defect in meningococcal internalization into HBMEC and
l
-glutamate uptake in the Δ
gltT-
Δ
gltM
mutant were suppressed only in strains expressing both GltT and GltM proteins. The efficiency of meningococcal invasion to HBMEC decreased under
l
-glutamate-depleted conditions. Furthermore, ezrin, a key membrane-cytoskeleton linker, accumulated beneath colonies of the
gltT

+

-gltM

+

N. meningitidis
strain but not of the Δ
gltT-
Δ
gltM
mutant. These findings suggest that
l
-glutamate influx via the GltT-GltM
l
-glutamate ABC transporter serves as a cue for
N. meningitidis
internalization into host cells.
Pasteurella multocidaToxin-Stimulated Osteoclast Differentiation Is B Cell Dependent
Authors: Hildebrand Dagmar , Heeg Klaus , Kubatzky Katharina F.
Published: October 2010

Pasteurella multocidais a Gram-negative bacillus that infects a number of wild and domestic animals, causing respiratory diseases. ToxigenicPasteurella multocidastrains produce a protein toxin (PMT) that leads to atrophic rhinitis in swine due to enhanced osteoclastogenesis and the inhibition of osteoblast function. We show that PMT-induced osteoclastogenesis is promoted by an as-yet-uncharacterized B-cell population. The toxin, however, is not acting at the level of hematopoietic stem cells, since purified CD117+cells from murine hematopoietic progenitor cells cultivated with PMT did not mature into osteoclasts. The early macrophages contained within this cell population (CD117+/CD11b+) did not further differentiate into osteoclasts but survived and were able to phagocytose. Within the CD117−population, however, we detected PMT-induced generation of a B220+/CD19+and B220+/IgM+B-cell population that was able to take up fluorescently labeled PMT. Using purified B-cell and macrophage populations, we show that these B cells are needed to efficiently generate osteoclasts from macrophages. Cells of the immune system are thought to affect osteoclast formation and function by secreting cytokines and growth factors. We show here that PMT-stimulated B cells produce elevated levels of the osteoclastogenic factors interleukin-1β (IL-1β), IL-6, tumor necrosis factor alpha, and receptor activator of nuclear factor receptor ligand (RANKL) compared to B cells generated through incubation with IL-7. These results suggest that the osteoclastic properties characteristic for PMT may result from a cross talk between bone cells and lymphoid cells and that B cells might be an important target ofPasteurella multocida.
Identification of Immunodominant Antigens by Probing a WholeChlamydia trachomatisOpen Reading Frame Proteome Microarray Using Sera from Immunized Mice
Authors: Cruz-Fisher Maria I. , Cheng Chunmei , Sun Guifeng , Pal Sukumar , Teng Andy , Molina Douglas M. , Kayala Matthew A. , Vigil Adam , Baldi Pierre , Felgner Philip L. , Liang Xiaowu , de la Maza Luis M.
Published: October 2010

Chlamydia trachomatisinfections can lead to severe chronic complications, including trachoma, ectopic pregnancy, and infertility. The only effective approach to disease control is vaccination. The goal of this work was to identify new potential vaccine candidates through a proteomics approach. We constructed a protein chip array (Antigen Discovery, Inc.) by expressing the open reading frames (ORFs) fromC. trachomatismouse pneumonitis (MoPn) genomic and plasmid DNA and tested it with serum samples from MoPn-immunized mice. Two groups of BALB/c female mice were immunized either intranasally or intravaginally with live elementary bodies (EB). Another two groups were immunized by a combination of the intramuscular and subcutaneous routes with UV-treated EB (UV-EB), using either CpG and Montanide as adjuvants to favor a Th1 response or alum to elicit a Th2 response. Serum samples collected at regular intervals postimmunization were tested in the proteome array. The microarray included the expression products of 909 proteins from a total of 921 ORFs of theChlamydiaMoPn genome and plasmid. A total of 185 immunodominant proteins elicited an early and sustained antibody response in the mice immunized with live EB, and of these, 71 were also recognized by the sera from mice immunized with UV-EB. The reactive antigens included some proteins that were previously described as immunogenic, such as the major outer membrane protein, OmpB, Hsp60, and IncA and proteins from the type III secretion system. In addition, we identified in mice several new immunogens, including 75 hypothetical proteins. In summary, we have identified a new group of immunodominant chlamydial proteins that can be tested for their ability to induce protection.
Quality control and monitoring schemes
Authors: Manser Paul
Published: October 2010

Providing a quality service demands checks, controls and established procedures. To assure customers and management that these are being done requires records, documents and audits, leading inevitably (and unfortunately) to increased administration and paperwork. However, these measures should not be viewed in a negative way. Their adoption can have significant benefits for the efficiency of an organisation. This article discusses quality control within the laboratory and looks at the various quality monitoring schemes and their relevance to the veterinary practice and laboratory.
What's in a logo?
Authors: Smith Jane
Published: October 2010

Effective logos are instantly recognisable, such as those for Coca‐Cola, IBM and British Telecom. Design is fundamental and, likewise, a good piece of print will not only convey information in a clear manner but will do so with style.
It shouldn't happen to a vet… Another tale from the VDS casebook
Authors: Tindall John
Published: October 2010

The Veterinary Defence Society receives a considerable number of claims relating to the pre‐purchase examination of horses. The reasons for the claims vary from purchasers finding that their choice does not live up to their expectations (and trying to blame the unfortunate veterinary surgeon who examined the horse), to there being actual defects which the vet missed or misinterpreted at the time of examination. The question of the true age of an animal is also a common cause for complaint. If there is doubt, therefore, it is advisable to say so and allow the vendors to produce documentary evidence to back their assertions. There is tremendous merit in bracketing all mouths that appear to be above eight years or aged as ‘over eight’, rather than trying to be too specific.