bluuebunny/crossref_metadata_2025 huggingface dataset:
Time reversal communication over doubly spread channels
Authors: Zeng Wen-Jun , Jiang Xue
Published: November 2012

Conventional time reversal can mitigate multipath delay dispersion by temporal focusing. But it is not applicable to time-varying channels with a Doppler spread. Although recently time reversal communication has been adapted to time-variant channels, the modified technique requires frequent channel updates to track channel variations and cannot handle large Doppler spread, which means that it cannot achieve frequency focusing. In this paper, two time reversal receivers for underwater acoustic communications over doubly spread channels are proposed. The proposed approach, which can be interpreted as time-frequency channel matching, is based on the channel spreading function rather than impulse response adopted by the existing techniques; this leads to much less frequent channel updates. Unlike existing methods that only correct a single Doppler shift, the proposed approach uses a rake-like structure to compensate for multiple Doppler shifts and hence can eliminate severe Doppler spread induced by temporal channel variations. Simulation results verify the effectiveness of the proposed approach, indicating that it can simultaneously counteract delay and Doppler spreads, achieving both temporal and frequency focusing.
Distortion-product otoacoustic emission suppression tuning curves in hearing-impaired humans
Authors: Gruhlke Alyson , Birkholz Cori , Neely Stephen T. , Kopun Judy , Tan Hongyang , Jesteadt Walt , Schmid Kendra , Gorga Michael P.
Published: November 2012

Distortion-product otoacoustic emission (DPOAE) suppression tuning curves (STCs) were measured in 65 hearing-impaired (HI) subjects at f2 frequencies of 2.0, 2.8, 4.0, and 5.6 kHz and L2 levels relative to sensation level (SL) from 10 dB to as much as 50 dB. Best frequency, cochlear-amplifier gain (tip-to-tail difference, T-T), and tuning (QERB) were estimated from STCs. As with normal-hearing (NH) subjects, T-T differences and QERB decreased as L2 increased. T-T differences and QERB were reduced in HI ears (compared to normal) for conditions in which L2 was fixed relative to behavioral threshold (dB SL). When STCs were compared with L2 at constant sound pressure levels (dB SPL), differences between NH and HI subjects were reduced. The large effect of level and small effect of hearing loss were both confirmed by statistical analyses. Therefore, the magnitude of the differences in DPOAE STCs between NH and HI subjects is mainly dependent on the manner in which level (L2) is specified. Although this conclusion may appear to be at odds with previous, invasive measures of cochlear-response gain and tuning, the apparent inconsistency may be resolved when the manner of specifying stimulus level is taken into account.
A model for the relation between stimulus frequency and spontaneous otoacoustic emissions in lizard papillae
Authors: Wit Hero P. , van Dijk Pim , Manley Geoffrey A.
Published: November 2012

Spontaneous otoacoustic emissions (SOAEs) and stimulus frequency otoacoustic emissions (SFOAEs) have been described from lizard ears. Although there are several models for these systems, none has modeled the characteristics of both of these types of otoacoustic emissions based upon their being derived from hair cells as active oscillators. Data from the ears of two lizard species, one lacking a tectorial membrane and one with a chain of tectorial sallets, as described by Bergevin et al. [“Coupled, active oscillators and lizard otoacoustic emissions,” AIP Conf. Proc. 1403, 453 (2008)], are modeled as an array of coupled self-sustained oscillators. The model, originally developed by Vilfan and Duke [“Frequency clustering in spontaneous otoacoustic emissions from a lizard's ear,” Biophys. J. 95, 4622–4630 (2008)], well describes both the amplitude and phase characteristics of SFOAEs and the relation between SFOAEs and SOAEs.
A classification based approach to speech segregation
Authors: Han Kun , Wang DeLiang
Published: November 2012

A key problem in computational auditory scene analysis (CASA) is monaural speech segregation, which has proven to be very challenging. For monaural mixtures, one can only utilize the intrinsic properties of speech or interference to segregate target speech from background noise. Ideal binary mask (IBM) has been proposed as a main goal of sound segregation in CASA and has led to substantial improvements of human speech intelligibility in noise. This study proposes a classification approach to estimate the IBM and employs support vector machines to classify time-frequency units as either target- or interference-dominant. A re-thresholding method is incorporated to improve classification results and maximize hit minus false alarm rates. An auditory segmentation stage is utilized to further improve estimated masks. Systematic evaluations show that the proposed approach produces high quality estimated IBMs and outperforms a recent system in terms of classification accuracy.
On the sound absorption by openings in rooms (L)
Authors: Martellotta Francesco
Published: November 2012

Sound absorption by openings has been rarely considered in room acoustics. In fact, information about small openings (such as ventilation grids) may sometimes be found, but nothing is said about larger openings, possibly as a consequence of the less likely occurrence in a design. In order to fill this gap, measurements were carried out in scale models, measuring the equivalent absorption due to different openings and comparing it with theoretical results. A “practical” model, showing a simple dependence on the opening dimension, was finally obtained and subsequently validated by measurements in a real room.
A numerical investigation of the Fick's law of diffusion in room acoustics
Authors: Visentin Chiara , Prodi Nicola , Valeau Vincent , Picaut Judicaël
Published: November 2012

In this paper the validity of the Fick's law of diffusion in room acoustics is investigated in the stationary state. The Fick's law, underlying the room-acoustics diffusion model, assumes a proportionality relationship between the local sound intensity and the energy density gradient, the proportionality constant being the so-called diffusion coefficient. This relationship, based on an analogy with the behavior of real particles in a scattering medium, is assessed by using a numerical tool simulating the actual dynamics of sound particles in a room. Two types of room geometries are considered: rooms with proportionate dimensions and long rooms. Concerning proportionate rooms the numerical analysis highlights the presence of weak variations of the reverberant energy density, generating an intensity vector pattern which is shown to be correctly described by the theoretical Fick's law and homogeneous diffusion. Conversely, inside long rooms, an estimate of the local value of the diffusion coefficient is carried out, showing that the reverberant sound field is well described by a spatially varying diffusion coefficient (non-homogeneous diffusion). The rate of increase of the estimated diffusion coefficient depends on the cross-sectional area of the room and on the boundaries absorption coefficient.
Spatiotemporal evolution of cavitation dynamics exhibited by flowing microbubbles during ultrasound exposure
Authors: Choi James J. , Coussios Constantin-C.
Published: November 2012

Ultrasound and microbubble-based therapies utilize cavitation to generate bioeffects, yet cavitation dynamics during individual pulses and across consecutive pulses remain poorly understood under physiologically relevant flow conditions. SonoVue® microbubbles were made to flow (fluid velocity: 10–40 mm/s) through a vessel in a tissue-mimicking material and were exposed to ultrasound [frequency: 0.5 MHz, peak-rarefactional pressure (PRP): 150–1200 kPa, pulse length: 1–100 000 cycles, pulse repetition frequency (PRF): 1–50 Hz, number of pulses: 10–250]. Radiated emissions were captured on a linear array, and passive acoustic mapping was used to spatiotemporally resolve cavitation events. At low PRPs, stable cavitation was maintained throughout several pulses, thus generating a steady rise in energy with low upstream spatial bias within the focal volume. At high PRPs, inertial cavitation was concentrated in the first 6.3 ± 1.3 ms of a pulse, followed by an energy reduction and high upstream bias. Multiple pulses at PRFs below a flow-dependent critical rate (PRFcrit) produced predictable and consistent cavitation dynamics. Above the PRFcrit, energy generated was unpredictable and spatially biased. In conclusion, key parameters in microbubble-seeded flow conditions were matched with specific types, magnitudes, distributions, and durations of cavitation; this may help in understanding empirically observed in vivo phenomena and guide future pulse sequence designs.
Acoustic wave propagation in equivalent fluid macroscopically inhomogeneous materials
Authors: Cieszko Mieczyslaw , Drelich Radoslaw , Pakula Michal
Published: November 2012

A one-dimensional problem of propagation of plane harmonic wave in macroscopically inhomogeneous materials is analyzed. A general description is proposed for the material of the equivalent fluid type characterized locally by two acoustical parameters: the wavenumber and the acoustical impedance. The coupled system of ordinary differential equations for amplitudes of forward and backward waves is derived. As an example the problem of wave interaction with a layer of inhomogeneous material placed between two homogeneous halfspaces is considered. The analytical solution and explicit expressions for reflection and transmission coefficients are obtained. It is shown that the presence of the inhomogeneous transition layer causes strong frequency dependence on both coefficients.
The influence of pipe organ reed curvature on tone quality
Authors: Plitnik George R. , Angster Judit
Published: November 2012

Although organ flue pipes have been widely studied, the same claim cannot be made for pipe organ reed stops. Given certain design constraints, such as the type of reed stop being voiced and the desired tone quality, the reed voicer must use consummate skill to curve the reed tongue so as to produce the best and most stable tone as well as to guarantee that each pipe blends with its neighbors. The amount and type of curve given to a reed tongue influences not only the harmonic structure of the steady-state sound but also the attack. There are two fundamentally different types of curvature that can be given to a reed tongue, the trompette (chorus reed) curve (which gives a bright sound) and the smooth-toned curve employed for clarinet pipes. This study investigated the effect of reed curvature on the vibration and tone (as assessed by professionals) on reed tongues of both types. Two F2 (8'F, 87.3 Hz) pipes (a trompette and a clarinet) were constructed and voiced with differently curved tongues to produce a variety of tones. The vibration of the reed tongue was measured under typical conditions by laser vibrometer; the pressure waves in the boot and in the shallot were measured by means of one-quarter inch microphones, and the pipe's sound was recorded at the egress. By performing various measurements simultaneously, phase differences were also determined, the extreme sensitivity of tone to reed curvature was demonstrated, and a recently proposed theory of reed vibration was shown to be more accurate than the standard model.
The vocal repertoire of the Key Largo woodrat (Neotoma floridana smalli)
Authors: Soltis Joseph , Alligood Christina A. , Blowers Tracy E. , Savage Anne
Published: November 2012

The Key Largo woodrat (Neotoma floridana smalli) is an endangered rodent endemic to the island of Key Largo, FL. There is little information on vocal communication in this species and descriptions of the acoustic structure of calls are lacking. A captive breeding program was established as part of the recovery plan for the species, providing the opportunity to investigate the vocal repertoire and acoustic structure of calls in both wild and captive contexts. Audio and video recordings were conducted at the Crocodile Lake National Wildlife Refuge in Key Largo and at Disney's Animal Kingdom®. Analysis of the acoustic structure of calls resulted in four provisional call types: “Tonal calls” consisted of “ultrasonic vocalizations” (40 kHz fundamental frequency, F0), “high squeaks” (10 kHz F0), and “squeaks” (1.8 kHz F0). “Noisy,” broadband calls known as “raspy” vocalizations did not exhibit fundamental frequencies, but contained several prominent spectral peaks (from 9 to 40 kHz). The social contexts of vocal production showed that all four call types were associated with pup need or interactions between pups and dams, and that raspy vocalizations were associated with courtship and copulation. Adults without pups exhibited little or no vocal activity, which may result from solitary lifestyles and predator avoidance.
Temporal summation of airborne tones in a California sea lion (Zalophus californianus)
Authors: Holt Marla M. , Ghoul Asila , Reichmuth Colleen
Published: November 2012

The trade-off between sound level and duration on hearing sensitivity (temporal summation) was investigated in a California sea lion (Zalophus californianus) using airborne pure-tone stimuli. Thresholds were behaviorally measured using the method of constant stimuli at 2.5, 5, and 10 kHz for nine signal durations ranging from 25 to 500 ms. In general, thresholds decreased as duration increased up to 300 ms, beyond which thresholds did not significantly improve. When these data were fitted separately to two versions of an exponential model, the estimated time constants (92–167 ms) were generally consistent between the two fits. However, the model with more free parameters generated fits with consistently higher R2 values, while avoiding potential arbitrary decisions about which data to include. The time constants derived for the California sea lion were generally consistent with those reported for other mammals, including other pinnipeds. The current study did not show a clear correlation between time constant and test frequency. The results should be considered when conducting audiometric work, assessing communications ranges, and evaluating potential noise impacts of airborne tonal signals on California sea lions.
Consonant recognition as a function of the number of stimulation channels in the Hybrid short-electrode cochlear implant
Authors: Reiss Lina A. J. , Turner Christopher W. , Karsten Sue A. , Erenberg Sheryl R. , Taylor Jessica , Gantz Bruce J.
Published: November 2012

Consonant recognition was measured as a function of the number of stimulation channels for Hybrid short-electrode cochlear implant (CI) users, long-electrode CI users, and normal-hearing (NH) listeners in quiet and background noise. Short-electrode CI subjects were tested with 1–6 channels allocated to a frequency range of 1063–7938 Hz. Long-electrode CI subjects were tested with 1–6, 8, or 22 channels allocated to 188–7938 Hz, or 1–6 or 15 channels from the basal 15 electrodes allocated to 1063–7938 Hz. NH listeners were tested with simulations of each CI group/condition. Despite differences in intracochlear electrode spacing for equivalent channel conditions, all CI subject groups performed similarly at each channel condition and improved up to at least four channels in quiet and noise. All CI subject groups underperformed relative to NH subjects. These preliminary findings suggest that the limited channel benefit seen for CI users may not be due solely to increases in channel interactions as a function of electrode density. Other factors such as pre-operative patient history, location of stimulation in the base versus apex, or a limit on the number of electric channels that can be processed cognitively, may also interact with the effects of electrode contact spacing along the cochlea.
Localization of small arms fire using acoustic measurements of muzzle blast and/or ballistic shock wave arrivals
Authors: Lo Kam W. , Ferguson Brian G.
Published: November 2012

The accurate localization of small arms fire using fixed acoustic sensors is considered. First, the conventional wavefront-curvature passive ranging method, which requires only differential time-of-arrival (DTOA) measurements of the muzzle blast wave to estimate the source position, is modified to account for sensor positions that are not strictly collinear (bowed array). Second, an existing single-sensor-node ballistic model-based localization method, which requires both DTOA and differential angle-of-arrival (DAOA) measurements of the muzzle blast wave and ballistic shock wave, is improved by replacing the basic external ballistics model (which describes the bullet's deceleration along its trajectory) with a more rigorous model and replacing the look-up table ranging procedure with a nonlinear (or polynomial) equation-based ranging procedure. Third, a new multiple-sensor-node ballistic model-based localization method, which requires only DTOA measurements of the ballistic shock wave to localize the point of fire, is formulated. The first method is applicable to situations when only the muzzle blast wave is received, whereas the third method applies when only the ballistic shock wave is received. The effectiveness of each of these methods is verified using an extensive set of real data recorded during a 7 day field experiment.
Effects of diotic fringes on interaural disparity detection (L)
Authors: Le Goff Nicolas , Kohlrausch Armin , Dau Torsten
Published: November 2012

Detection thresholds were measured for interaural time differences (ITDs) and interaural level differences (ILDs) that were carried by probe segments embedded in otherwise diotic broadband noise (fringe). The duration of the probe was varied between 5 and 200 ms, and the duration of the fringe was between 5 and 100 ms. Consistent with results of Akeroyd and Bernstein [(2001). J. Acoust. Soc. Am. 110, 2516–2526], it was found that a 5-ms fringe placed before a 5-ms probe (forward fringe) led to a larger threshold elevation than a 5-ms fringe placed after the probe (backward fringe). As suggested by Akeroyd and Bernstein, this effect was accounted for by a model providing an onset emphasis of a factor of 2. In contrast, for longer probe and fringe durations, which have not been tested before, a backward fringe had a stronger effect than a forward fringe. This surprising effect was accounted for by an extended model that provided an offset emphasis of a factor of 11 for a 50-ms probe and a 100-ms fringe.
Thermal and viscous effects on sound waves: Revised classical theory
Authors: Davis Anthony M. J. , Brenner Howard
Published: November 2012

In this paper the recently developed, bi-velocity model of fluid mechanics based on the principles of linear irreversible thermodynamics (LIT) is applied to sound propagation in gases taking account of first-order thermal and viscous dissipation effects. The results are compared and contrasted with the classical Navier–Stokes–Fourier results of Pierce for this same situation cited in his textbook. Comparisons are also made with the recent analyses of Dadzie and Reese, whose molecularly based sound propagation calculations furnish results virtually identical with the purely macroscopic LIT-based bi-velocity results below, as well as being well-supported by experimental data. Illustrative dissipative sound propagation examples involving application of the bi-velocity model to several elementary situations are also provided, showing the disjoint entropy mode and the additional, evanescent viscous mode.
An Interacting Binary System Powers Precessing Outflows of an Evolved Star
Authors: Boffin Henri M. J. , Miszalski Brent , Rauch Thomas , Jones David , Corradi Romano L. M. , Napiwotzki Ralf , Day-Jones Avril C. , Köppen Joachim
Published: November 2012

Not Single After All

Planetary nebulae form toward the end of the lives of sunlike stars. They appear after the star has shed its outer layers, and radiation from what is left of it ionizes the surrounding medium. Using the Very Large Telescope in Chile,

Boffin
et al.

(p.
773
) obtained spectra of the star at the center of Fleming 1, a point-symmetric planetary nebula with rotating bipolar jets. It has long been assumed that jets like these arose from an interacting binary system. Indeed, the data reveal that the central star in Fleming 1 has a companion in a very close orbit.
Discovery of an Organic Trefoil Knot
Authors: Ponnuswamy Nandhini , Cougnon Fabien B. L. , Clough Jessica M. , Pantoş G. Dan , Sanders Jeremy K. M.
Published: November 2012

An Organic Knot

When people tie knots, they grasp both ends of a strand and loop them around each other. The task is rather more difficult at the molecular level, when there is no top-down organizing framework, and the strand needs to be coaxed into looping around itself. Recently, chemists have taken advantage of the tight geometrical restrictions of metal-ligand coordination to produce knot morphologies.

Ponnuswamy
et al.

(p.
783
; see the Perspective by

Siegel

) now demonstrate the spontaneous assembly of a trefoil knot from organic fragments without assistance from metal centers. The topology appears to be driven by hydrophobic interactions among aromatic segments that minimize exposure to surrounding water through their overlap.
Law and Science Collide Over Human Gene Patents
Authors: Cook-Deegan Robert
Published: November 2012

Will the Supreme Court rule that DNA sequences found in nature cannot be patented?
A Single-Molecule Engine
Authors: Bockrath Marc W.
Published: November 2012

A single hydrogen molecule can be used to drive the tip motion of a scanning tunneling microscope.
Lung-on-a-Chip Breathes New Life Into Drug Discovery
Authors: Service Robert F.
Published: November 2012

An engineered "lung-on-a-chip" can faithfully model a serious respiratory ailment and accurately predict the toxicity of a compound that causes the disease and the ability of a new drug to prevent it.
Weather Forecasts Slowly Clearing Up
Authors: Kerr Richard A.
Published: November 2012

Ever-increasing computer power and new kinds of observations are driving weather prediction to new heights, but some kinds of weather are still not yielding.
Acquisition of Meningococcal Serogroup W-135 Carriage in Turkish Hajj Pilgrims Who Had Received the Quadrivalent Meningococcal Polysaccharide Vaccine
Authors: Ceyhan M. , Celik M. , Demir E. T. , Gurbuz V. , Aycan A. E. , Unal S.
Published: November 2012

Invasive meningococcal disease is a recognized public health problem worldwide, with a dynamic and changeable epidemiology. In Turkey, the second most common pathogenic meningococcal serogroup (after serogroup B) is W-135, including an epidemic in 2005, which has been strongly associated with Hajj pilgrims and their close contacts. In two studies conducted in 2010, we assessed meningococcal carriage in intending Turkish pilgrims to the Hajj when they attended to receive a plain polysaccharide vaccine against serogroups A, C, W-135, and Y and, upon their return, to determine the acquisition of meningococcal carriage by the pilgrims themselves and subsequently their household contacts. Nasopharyngeal swabs were obtained from pilgrims before the Hajj and upon their return. Swabs were then obtained from 39 household contacts of pilgrims who were shown to have acquired carriage during the Hajj. Of the 472 pilgrims before the Hajj, 63 (13%) were positive for meningococcal carriage, of which 52 cases (83%) were serogroup W-135. In the 296 pilgrims tested after the Hajj, 81 (27%) were positive for meningococcal carriage, including 74 (91%) with W-135. In 11 family members of pilgrims who acquired W-135 carriage at the Hajj, 10 (91%) had acquired carriage of serogroup W-135. This study illustrates the acquisition of meningococcal carriage, predominantly of serogroup W-135 by pilgrims attending the Hajj, and the transmission of this carriage to their family members on their return, explaining the source of W-135 meningococcal disease in Turkey.
Complete Genome Sequence of Burkholderia phenoliruptrix BR3459a (CLA1), a Heat-Tolerant, Nitrogen-Fixing Symbiont of Mimosa flocculosa
Authors: de Oliveira Cunha Cláudio , Goda Zuleta Luiz Fernando , Paula de Almeida Luiz Gonzaga , Prioli Ciapina Luciane , Lustrino Borges Wardsson , Pitard Rosa Maria , Baldani José Ivo , Straliotto Rosangela , de Faria Sérgio Miana , Hungria Mariangela , Sousa Cavada Benildo , Mercante Fábio Martins , Ribeiro de Vasconcelos Ana Tereza
Published: November 2012

The genus
Burkholderia
represents a challenge to the fields of taxonomy and phylogeny and, especially, to the understanding of the contrasting roles as either opportunistic pathogens or bacteria with biotechnological potential. Few genomes of nonpathogenic strains, especially of diazotrophic symbiotic bacteria, have been sequenced to improve understanding of the genus. Here, we contribute with the complete genome sequence of
Burkholderia phenoliruptrix
strain BR3459a (CLA1), an effective diazotrophic symbiont of the leguminous tree
Mimosa flocculosa
Burkart, which is endemic to South America.
Diversification of Clonal Complex 5 Methicillin-Resistant Staphylococcus aureus Strains (Rhine-Hesse Clone) within Germany
Authors: Schulte Berit , Bierbaum Gabriele , Pohl Konstanze , Goerke Christiane , Wolz Christiane
Published: November 2012

Since 1995, a methicillin-resistant
Staphylococcus aureus
(MRSA) clone has spread in southern Germany. The strain was assigned to the Rhine-Hesse pulsed-field gel electrophoresis (PFGE) type by the staphylococcal reference center and was highly similar to epidemic clones known to belong to clonal complex 5 (CC5; USA100) based on multilocus sequence typing (MLST). Here we analyzed a defined collection of strains assigned to the Rhine-Hesse/USA100 PFGE type. Using sequence-based typing methods (MLST,
spa
), the isolates were divided into two distinct clusters, ST5 and its single-locus variant ST225. These two lineages are not distinguishable by PFGE or phage typing. Most of the ST5 isolates were derived from patients and volunteers from the Tübingen area in southwest Germany, whereas the ST225 isolates were mostly from other locations in Germany. The locally restricted ST5 isolates were shown to contain different SSC
mec
islands and exhibited different antibiotic resistance profiles. In contrast, the ST225 isolates form a highly homogenous group and are emerging all over Germany. The two lineages are clearly distinguishable by their phage content and
spa
type: ST5 strains from Tübingen are characterized by a Sa7int phage that carries the virulence gene
sak
, which codes for staphylokinase, and ST225 isolates are characterized by a Sa1int phage. In conclusion, based on sequence typing and phage content, CC5 strains can be subdivided into two distinct lineages with different epidemicities.
Three-Way Comparison of BBL CHROMagar MRSA II, MRSA
Select
, and Spectra MRSA for Detection of Methicillin-Resistant Staphylococcus aureus Isolates in Nasal Surveillance Cultures
Authors: Denys Gerald A. , Renzi Pamela B. , Koch Kim M. , Wissel Carol M.
Published: November 2012

Methicillin-resistant
Staphylococcus aureus
(MRSA) is a major cause of hospital-acquired and life-threatening infections. Active surveillance programs for MRSA utilize either molecular or culture-based methods. A prospective study was performed to compare the performance of selective and differential chromogenic media, BBL CHROMagar MRSA II (CMRSA II; BD Diagnostics, Sparks, MD), MRSA
Select
(Bio-Rad Laboratories, Redmond, WA), and Spectra MRSA (Remel, Lenexa, KS), for the detection of MRSA in nasal swab specimens. A total of 515 compliant remnant nasal swab specimens were sequentially used to inoculate BBL Trypticase soy agar with 5% sheep blood (TSA II) and each chromogenic medium. After 24 h of incubation, colony color reactions and morphology on chromogenic media were compared to suspicious colonies on nonselective TSA II. MRSA on TSA II was confirmed by Gram staining, a coagulase test, and a cefoxitin disk test. The overall prevalence of MRSA and methicillin-susceptible
S. aureus
(MSSA) on TSA II was 12.4% (64/515) and 9.7% (50/515), respectively. When each chromogenic medium was compared to the standard culture method, the sensitivity and specificity, respectively, were as follows: CMRSA II, 87.7% and 98.6%; MRSA
Select
, 89.0% and 93.4%; and Spectra MRSA, 83.6% and 92.1%. The positive predictive values were highest for CMRSA II (91.4%), followed by MRSA
Select
(69.1%) and Spectra MRSA (63.5%). False-positive results on chromogenic media were mainly due to color interpretation. The negative predictive values for all three media were greater than 97%. In conclusion, CMRSA II gave the best overall results for detecting MRSA from nasal specimens.
Sensitivity and Specificity of
In Situ
Hybridization for Diagnosis of Cutaneous Infection by Leishmania infantum in Dogs
Authors: Menezes Rodrigo C. , Figueiredo Fabiano B. , Wise Annabel G. , Madeira Maria F. , Oliveira Raquel V. C. , Schubach Tânia M. P. , Kiupel Matti , Langohr Ingeborg M.
Published: November 2012

An accurate diagnosis of infection by
Leishmania infantum
in dogs is fundamental for the control of zoonotic visceral leishmaniasis (VL). Histopathology (HP) and immunohistochemistry (IHC) are frequently used for the histological diagnosis of
L. infantum
in dogs but have shown limited accuracy. To improve the sensitivity and specificity of the histological diagnosis of VL, we evaluated automated
in situ
hybridization (ISH) using a generic probe for
Leishmania
and a specific probe for
L. infantum
in surgical skin biopsy specimens of dogs. The ISH results were compared with those of HP and IHC, using parasitological culture as the reference standard. Skin samples from 51 dogs with cutaneous
L. infantum
infection and 51 noninfected dogs were randomly selected from samples of dogs from various cities in Brazil where canine VL is endemic. These samples were processed for parasitological culture, HP, IHC, and ISH using both probes. The sensitivities of ISH using the specific probe, ISH using the generic probe, IHC, and HP were, respectively, 74.5%, 70.6%, 69.5%, and 57.6%. The specificity of both ISH probes tested was 100%, and there was no cross-hybridization of the generic and specific probes with selected pathogenic fungi and protozoa. The specific probe discriminated
L. infantum
from the other species of
Leishmania
that infect dogs in the New World. ISH is highly sensitive and specific for the diagnosis of
L. infantum
in histologic samples of skin from infected dogs and can be used on routine biopsy material to make a diagnosis of leishmaniasis.
Sonication versus Vortexing of Implants for Diagnosis of Prosthetic Joint Infection
Authors: Portillo María Eugenia , Salvadó Margarita , Trampuz Andrej , Plasencia Virginia , Rodriguez-Villasante María , Sorli Lluisa , Puig Lluis , Horcajada Juan Pablo
Published: November 2012

Biofilm removal efficacy of vortexing alone was compared with the standard vortexing-sonication procedure. Among 135 removed prostheses, 35 were diagnosed with infection and 100 with aseptic failure. At a cutoff of ≥50 CFU/ml, sonication was more sensitive than vortexing (60% versus 40%,
P
= 0.151), while the specificity was 99% for both methods.
The Replication Defect of ICP0-Null Mutant Herpes Simplex Virus 1 Can Be Largely Complemented by the Combined Activities of Human Cytomegalovirus Proteins IE1 and pp71
Authors: Everett Roger D. , Bell Adam J. , Lu Yongxu , Orr Anne
Published: November 2012

Herpes simplex virus 1 (HSV-1) immediate-early protein ICP0 is required for efficient lytic infection and productive reactivation from latency and induces derepression of quiescent viral genomes. Despite being unrelated at the sequence level, ICP0 and human cytomegalovirus proteins IE1 and pp71 share some functional similarities in their abilities to counteract antiviral restriction mediated by components of cellular nuclear structures known as ND10. To investigate the extent to which IE1 and pp71 might substitute for ICP0, cell lines were developed that express either IE1 or pp71, or both together, in an inducible manner. We found that pp71 dissociated the hDaxx-ATRX complex and inhibited accumulation of these proteins at sites juxtaposed to HSV-1 genomes but had no effect on the promyelocytic leukemia protein (PML) or Sp100. IE1 caused loss of the small ubiquitin-like modifier (SUMO)-conjugated forms of PML and Sp100 and inhibited the recruitment of these proteins to HSV-1 genome foci but had little effect on hDaxx or ATRX in these assays. Both IE1 and pp71 stimulated ICP0-null mutant plaque formation, but neither to the extent achieved by ICP0. The combination of IE1 and pp71, however, inhibited recruitment of all ND10 proteins to viral genome foci, stimulated ICP0-null mutant HSV-1 plaque formation to near wild-type levels, and efficiently induced derepression of quiescent HSV-1 genomes. These results suggest that ND10-related intrinsic resistance results from the additive effects of several ND10 components and that the effects of IE1 and pp71 on subsets of these components combine to mirror the overall activities of ICP0.
Human T Cell Leukemia Virus Type 2 Tax-Mediated NF-κB Activation Involves a Mechanism Independent of Tax Conjugation to Ubiquitin and SUMO
Authors: Journo Chloé , Bonnet Amandine , Favre-Bonvin Arnaud , Turpin Jocelyn , Vinera Jennifer , Côté Emilie , Chevalier Sébastien Alain , Kfoury Youmna , Bazarbachi Ali , Pique Claudine , Mahieux Renaud
Published: November 2012

Permanent activation of the NF-κB pathway by the human T cell leukemia virus type 1 (HTLV-1) Tax (Tax1) viral transactivator is a key event in the process of HTLV-1-induced T lymphocyte immortalization and leukemogenesis. Although encoding a Tax transactivator (Tax2) that activates the canonical NF-κB pathway, HTLV-2 does not cause leukemia. These distinct pathological outcomes might be related, at least in part, to distinct NF-κB activation mechanisms. Tax1 has been shown to be both ubiquitinated and SUMOylated, and these two modifications were originally proposed to be required for Tax1-mediated NF-κB activation. Tax1 ubiquitination allows recruitment of the IKK-γ/NEMO regulatory subunit of the IKK complex together with Tax1 into centrosome/Golgi-associated cytoplasmic structures, followed by activation of the IKK complex and RelA/p65 nuclear translocation. Herein, we compared the ubiquitination, SUMOylation, and acetylation patterns of Tax2 and Tax1. We show that, in contrast to Tax1, Tax2 conjugation to endogenous ubiquitin and SUMO is barely detectable while both proteins are acetylated. Importantly, Tax2 is neither polyubiquitinated on lysine residues nor ubiquitinated on its N-terminal residue. Consistent with these observations, Tax2 conjugation to ubiquitin and Tax2-mediated NF-κB activation is not affected by overexpression of the E2 conjugating enzyme Ubc13. We further demonstrate that a nonubiquitinable, non-SUMOylable, and nonacetylable Tax2 mutant retains a significant ability to activate transcription from a NF-κB-dependent promoter after partial activation of the IKK complex and induction of RelA/p65 nuclear translocation. Finally, we also show that Tax2 does not interact with TRAF6, a protein that was shown to positively regulate Tax1-mediated activation of the NF-κB pathway.
Nucleolar Trafficking of the Mouse Mammary Tumor Virus Gag Protein Induced by Interaction with Ribosomal Protein L9
Authors: Beyer Andrea R. , Bann Darrin V. , Rice Breanna , Pultz Ingrid S. , Kane Melissa , Goff Stephen P. , Golovkina Tatyana V. , Parent Leslie J.
Published: November 2012

The mouse mammary tumor virus (MMTV) Gag protein directs the assembly in the cytoplasm of immature viral capsids, which subsequently bud from the plasma membranes of infected cells. MMTV Gag localizes to discrete cytoplasmic foci in mouse mammary epithelial cells, consistent with the formation of cytosolic capsids. Unexpectedly, we also observed an accumulation of Gag in the nucleoli of infected cells derived from mammary gland tumors. To detect Gag-interacting proteins that might influence its subcellular localization, a yeast two-hybrid screen was performed. Ribosomal protein L9 (RPL9 or L9), an essential component of the large ribosomal subunit and a putative tumor suppressor, was identified as a Gag binding partner. Overexpression of L9 in cells expressing the MMTV(C3H) provirus resulted in specific, robust accumulation of Gag in nucleoli. Förster resonance energy transfer (FRET) and coimmunoprecipitation analyses demonstrated that Gag and L9 interact within the nucleolus, and the CA domain was the major site of interaction. In addition, the isolated NC domain of Gag localized to the nucleolus, suggesting that it contains a nucleolar localization signal (NoLS). To determine whether L9 plays a role in virus assembly, small interfering RNA (siRNA)-mediated knockdown was performed. Although Gag expression was not reduced with L9 knockdown, virus production was significantly impaired. Thus, our data support the hypothesis that efficient MMTV particle assembly is dependent upon the interaction of Gag and L9 in the nucleoli of infected cells.
Acute myocardial infarction in a young patient with hyperhomocysteinaemia
Authors: Ukachukwu Vincent , Idris Salah , McIlwee Alister
Published: November 2012

Homocysteinuria is a rare inborn error of metabolism known to be associated with an increased risk of vascular events. A 36-year-old Caucasian man presented with a 2day history of epigastric discomfort associated with nausea and sweating. He has a history of homocysteinuria and had been poorly compliant with treatment. An ECG showed ST-segment elevation and Q-waves in anterior leads. Blood tests showed markedly elevated high-sensitivity troponin and high homocysteine levels. He had a failed primary percutaneous coronary intervention due to extensive thrombus in the left anterior descending artery, which was aspirated and he received integrelin infusion for 48 h. Echocardiogram showed mild-to-moderate impairment of left ventricular function with apical akinesis extending to the mid-portion of anteroseptal walls consistent with anterior myocardial infarction. He was started on homocysteine-lowering treatment with betaine and folic acid. He is now on follow-up with clinical chemistry and cardiac rehabilitation.
Heat stress, health and well-being: findings from a large national cohort of Thai adults
Authors: Tawatsupa Benjawan , Yiengprugsawan Vasoontara , Kjellstrom Tord , Seubsman Sam-ang , Sleigh Adrian ,   the Thai Cohort Study Team
Published: November 2012

Objectives

This study aims to examine the association between self-reported heat stress interference with daily activities (sleeping, work, travel, housework and exercise) and three graded-holistic health and well-being outcomes (energy, emotions and life satisfaction).

Design

A cross-sectional study.

Setting

The setting is tropical and developing countries as Thailand, where high temperature and high humidity are common, particularly during the hottest seasons.

Participants

This study is based on an ongoing national Thai Cohort Study of distance-learning open-university adult students (N=60 569) established in 2005 to study the health-risk transition.

Primary and secondary outcome measures

Health impacts from heat stress in our study are categorised as physical health impacts (energy levels), mental health impacts (emotions) and well-being (life satisfaction). For each health and well-being outcome we report ORs and 95% CIs using multinomial logistic regression adjusting for a wide array of potential confounders.

Results

Negative health and well-being outcomes (low-energy level, emotional problems and low life satisfaction) associated with increasing frequency of heat stress interfering with daily activities. Adjusted ORs for emotional problems were between 1.5 and 4.8 and in general worse than energy level (between 1.31 and 2.91) and life satisfaction (between 1.10 and 2.49). The worst health outcomes were when heat interfered with sleeping, followed by interference with daily travel, work, housework and exercise.

Conclusions

In tropical Thailand there already are substantial heat stress impacts on health and well-being. Increasing temperatures from climate change plus the ageing and urbanisation of the population could significantly worsen the situation. There is a need to improve public health surveillance and public awareness regarding the risks of heat stress in daily life.
Good grief: bereavement literature for young adults andA Monster Calls
Authors: Day Giskin
Published: November 2012

Recent years have seen a proliferation of critically acclaimed novels for young adults dealing with bereavement. This is part of a ‘bereavement turn’—a contemporary cultural movement to examine publicly our attitudes to death and grieving. This paper examines the narrative strategies in Patrick Ness's award-winning novelA Monster Callsto look at the ways in which the psychic burden of the impending loss of a parent through cancer is managed. The book draws on conventions of children's literature to create a sense of familiarity that helps to balance the emotional stress of the story. The Kübler-Ross stages of grief serve as a heuristic that helps the story deliver catharsis in spite of its inevitably traumatic subject matter.A Monster Callsis an important addition to the canon of fictional pathography.
Cardiovascular drift in trained paraplegic and able-bodied individuals during prolonged wheelchair exercise: effect of fluid replacement
Authors: Zacharakis Emmanouil D. , Kounalakis Stylianos N. , Nassis George P. , Geladas Nickos D.
Published: November 2012

The progressive heart rate (HR) increase and stroke volume (SV) decline during prolonged constant-load leg exercise signifies cardiovascular drift (CVdrift); fluid replacement is known to minimize this phenomenon. Like their able-bodied counterparts (AB), paraplegic athletes undergo prolonged exercise during training and competition, which could result in CVdrift. The aim of this study is to address the role of rehydration on preventing CVdrift in spinal cord injured (SCI) paraplegic athletes. Eight SCI athletes with an injury level between C7 and T6 and 9 AB subjects performed 60-min constant-load exercise on a wheelchair ergometer in a thermo-neutral environment. No fluid was taken in 1 trial, whereas 85% of sweat losses were replaced by drinking water in another trial. Cardic output (CO), SV, HR, and oral temperature (Tor) were determined during exercise. Prolonged exercise resulted in similar HR (18 beats·min−1 for AB and 12 beats·min−1 for SCI) and Tor (0.63 °C for AB and 0.71 °C for SCI) elevation and SV decline (−8.5 mL·beat−1 for AB and −5.5 mL·beat−1 for SCI), whereas CO remained unchanged. Water intake restrained the exercise-induced hyperthermia and resulted in smaller SV decline (−4.0 mL for AB and −3.0 mL for SCI, p < 0.01). In conclusion, CVdrift was similar in SCI and AB subjects during prolonged wheelchair exercise. Likewise, the beneficial effects of hydration in both groups were analogous.
Raman spectral analysis of nasopharyngeal carcinoma cell line CNE2 after microwave radiation
Authors: Ye Yuhuang , Chen Yang , Su Ying , Zou Changyan , Huang Yangwen , Ou Lin , Chen Rong
Published: November 2012

This study aimed to study the effects of microwave radiation on the nasopharyngeal carcinoma cell line CNE2 by Raman spectroscopy. The cells were separated into a control group and radiated groups with radiation times of 2, 5, 10, and 25 min, respectively. Both principal components analysis and support vector machine were employed for statistical analysis of Raman spectra. The results show that the relative content of C-H deformation and amide I begin to change when the radiation time is over 10 min, and principal components analysis further confirms there are significant differences after 10 min of radiation. Moreover, support vector machine is simultaneously used to classify radiated samples from control samples. The classification accuracy is low until the radiation time reaches over 10 min. In conclusion, this study reveals the Raman spectral characteristics of CNE2 under different microwave radiation exposure timesand demonstrates Raman spectroscopy can be a potential method to explore cellular characterization after radiation. The final results may help in elucidating the mechanism by which microwave radiation interacts with tumor cells.
Stress rate sensitivity of Paskapoo sandstone under flexure
Authors: Islam Md Toihidul , Bindiganavile Vivek
Published: November 2012

This paper evaluates the dynamic flexural response of sandstone from the Paskapoo formation in Alberta. Sandstone prisms were subjected to quasi-static flexure as per ASTM while a drop-weight impact tester was employed to generate stress rates up to 108 kPa/s. Companion testing under quasi-static compression on sandstone cylinders helped establish baseline properties including the compressive strength, elastic modulus, and Poisson’s ratio. It was found that the flexural strength and fracture toughness of Paskapoo sandstone obey stress rate sensitive models developed originally for concrete. However, the fracture toughness was more stress rate sensitive than its flexural strength.
OBSERVATIONAL CONSTRAINTS ON D-TERM BRANEWORLD INFLATION
Authors: SAFSAFI A. , BOUAOUDA A. , CHAKIR H. , INCHAOUH J. , BENNAI M.
Published: November 2012

We consider a supersymmetric hybrid inflation in the framework of the Randall–Sundrum type-2 braneworld model. We derive an analytical expression for the effective scalar potential and find that the D-term dominates hybrid inflation process. We show that we can eliminate partially the fine tuning problem related to coupling constant λ of the potential and calculate the value of FI-term ξ according to recent WMAP7 observation data. We show also that some inflationary spectrum parameters, in particular, the ratio r and the running [Formula: see text] are widely consistent with WMAP7, BAO and H0 data.
HIGGS PHYSICS AND SUPERSYMMETRY
Authors: NATH PRAN
Published: November 2012

A brief overview of Higgs physics and of supersymmetry is given. The central theme of the overview is to explore the implications of the recent discovery of a Higgs-like particle regarding the prospects for the discovery of supersymmetry assuming that it is indeed the spin-0 CP even boson that enters in the spontaneous breaking of the electroweak symmetry. The high mass of the Higgs-like boson at ~125 GeV points to the weak scale of supersymmetry that enters in the loop correction to the Higgs boson mass, to be relatively high, i.e. in the TeV region. However, since more than one independent mass scales enter in softly broken supersymmetry, the allowed parameter space of supersymmetric models can allow a small Higgs mixing parameter μ and light gaugino masses consistent with a ~125 GeV Higgs boson mass. Additionally some light third generation sfermions, i.e. the stop and the stau are also permissible. Profile likelihood analysis of a class of SUGRA models indicates that mA>300 GeV which implies one is in the decoupling phase and the Higgs couplings are close to the standard model in this limit. Thus a sensitive measurement of the Higgs couplings with fermions and with the vector bosons is needed to detect beyond the standard model effects. Other topics discussed include dark matter, proton stability, and the Stueckelberg extended models as probes of new physics. A brief discussion of the way forward in the post Higgs discovery era is given.
GENUINE CORRELATIONS IN FINITE-SIZE SPIN SYSTEMS
Authors: GIORGI GIAN LUCA , BUSCH THOMAS
Published: November 2012

Genuine multipartite correlations in finite-size XY chains are studied as a function of the applied external magnetic field. We find that, for low temperatures, multipartite correlations are sensitive to the parity change in the Hamiltonian ground state, given that they exhibit a minimum every time that the ground state becomes degenerate. This implies that they can be used to detect the factorizing point, that is, the value of the external field such that, in the thermodynamical limit, the ground state becomes the tensor product of single-spin states.