bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical and Experimental Study on the Heat Transfer and Pressure Drop of Compact Cross-Corrugated Recuperators
Authors: Guo-Yan Zhou , Shan-Tung Tu , Hu-Gen Ma
Published: March 2014

Recuperator is one of the key components in high temperature gas cooled reactors. Although cross-corrugated plates have been used to increase the thermal performance of the recuperators, the fundamental mechanisms of fluid flow and heat transfer are generally not clear. Fluid dynamics simulations and experiments are hence carried out to study the performance of the recuperators. A periodic cell is employed as the control volume. The flow field and heat transfer in sine-wave crossed-corrugated channels are investigated based on the Navier–Stokes and energy equations in the laminar flow regime between Re = 84 and 1168. The numerical results of the heat transfer factors and friction factors in different operating conditions show a fairly good agreement with the experimental measurements. The influence factors on the heat transfer and the hydraulic performance are also discussed in the paper. It is found that the heat transfer factor j and friction factor f decrease with the increase of the pitch-height ratio for a given Reynolds number.
Determination of the Lumped-Capacitance Parameters of Air-Cooled Servers Through Air Temperature Measurements
Authors: Salih Erden Hamza , Ezzat Khalifa H. , Schmidt Roger R.
Published: March 2014

Computer servers can be represented by lumped thermal capacitances for the purpose of simulating server and data center transient thermal response to changes in operating conditions or equipment failures. Two parameters are needed to characterize the transient behavior of a lumped-capacitance server: its thermal capacitance and its thermal conductance, heat transfer effectiveness, or time constant. To avoid the laborious task of obtaining these parameters from measurements or estimations of the thermal characteristics of internal components of the server, a method is proposed to derive these parameters from external measurements that can be easily obtained without performing an “autopsy” on the server. In this paper, we present the mathematical formulation underlying the proposed method and describe how the parameters are to be obtained from external air-temperature measurements using the mathematical model. We then present validation test cases using experimental data from server shut-down and inlet-temperature ramp tests. The experimentally obtained parameters are implemented into a computational fluid dynamics (CFD) case study of server shutdown in which the transient server exit air temperature is computed from the lumped-capacitance parameters via a user-defined function. The results thus obtained are in excellent agreement with the experimental data.
Computational Fluid Dynamic Analysis of Eccentric Atomization Spray Cooling Nozzle Designs for Micromachining
Authors: Lunardelli Andressa , Wentz John E.
Published: March 2014

A recent development in cooling and lubrication technology for micromachining processes is the use of atomized spray cooling systems. These systems have been shown to be more effective than traditional methods of cooling and lubrication for extending tool life in micromachining. Typical nozzle systems for atomization spray cooling incorporate the mixing of high-speed gas and an atomized fluid carried by a gas stream. In a two-phase atomization spray cooling system, the atomized fluid can easily access the tool–workpiece interface, removing heat through evaporation and lubricating the region by the spreading of oil micro-droplets. The success of the system is determined in a large part by the nozzle design, which determines the atomized droplet's behavior at the cutting zone. In this study, computational fluid dynamics are used to investigate the effect of nozzle design on droplet delivery to the tool. An eccentric-angle nozzle design is evaluated through droplet flow modeling. A design of simulations methodology is used to study the design parameters of initial droplet velocity, high-speed gas velocity, and the angle change between the two inlets. The system is modeled as a steady-state multiphase system without phase change, and droplet interaction with the continuous phase is dictated in the model by drag forces and fluid surface tension. The Lagrangian method, with a one-way coupling approach, is used to analyze droplet delivery at the cutting zone. Following a factorial experimental design, deionized water droplets and a semisynthetic cutting fluid are evaluated through model simulations. Statistical analysis of responses (droplet velocity at tool, spray thickness, and droplet density at tool) show that droplet velocity is crucial for the nozzle design and that modifying the studied parameters does not change droplet density in the cutting zone.
The Importance of Vacuum and Remelting Practices in a Modern Specialty Steel Plant. Part II: The Production of Different Specialty Steels
Authors: Mueller-Aue H. J. , Spitzer H. , Tesche K. , Zingel G.
Published: March 2014

The various groups of specialty steels require different melting techniques, treatments, pouring methods, and remelting processes. Depending on their composition and application, quality and cost are significant factors governing the decision for a specific procedure. For example, the two-stage technique—UHP electric furnace or BOF-vacuum plant—is successful in the production of anti-friction bearing steel, in that it reduces the oxide content and produces a more consistent product. In the production of alloyed engineering steels, as used by the automotive industry, excellent results are obtained with this same two-step method. This method reduces melting times with gains in purity and closer control of alloying content and grain size. For special requirements such as aircraft engines, the steel is vacuum-melted and vacuum-remelted. Precision forgings require degassing treatments and with unusual specifications for purity and freedom from segregation vacuum-arc or electro-slag remelting. Special purity tool steels are initially melted in the arc furnace or oxygen converter and then treated under vacuum. Widespread use is made of the possible variations in the two-stage arrangement, “melting furnace-vacuum plant”, in the production of stainless steels. As opposed to the traditional methods of producing this type of steel, appropriate combinations result in significant cost and quality advantages. High purity stainless steels, particularly in the form of flat shapes, are commonly VAR- or ESR-remelted. However, the most pronounced effects in melting, vacuum treatment, and remelting are found in the field of high-temperature materials.
Effect of high-pressure torsion deformation on surface properties and biocompatibility of Ti-50.9 mol. %Ni alloys
Authors: Awang Shri Dayangku Noorfazidah , Tsuchiya Koichi , Yamamoto Akiko
Published: March 2014

Ti-50.9 mol. %Ni was subjected to high-pressure torsion (HPT) deformation for different number of rotations (N) of 0.25, 0.5, 1, 5, and 10. The structural changes induced by HPT were analyzed using x-ray diffractometer (XRD). The surfaces of the samples before and after cell culture were characterized using x-ray photoelectron spectroscopy (XPS). The biocompatibility of the samples was evaluated based on a colony formation assay, nickel ion release, and protein adsorption behavior. XRD analysis revealed the occurrence of grain refinement, phase transformation, and amorphization in the TiNi samples by HPT deformation due to high dislocation density. The changes in chemical composition and thickness of the passive film formed on the surface observed in XPS analysis reveals improvement in the stability of the passive film by HPT deformation. The microstructural change due to the deformation was found to influence the biocompatibility behaviors of TiNi. Plating efficiency and protein adsorption were found to be higher when the samples are in stress-induced martensitic or amorphous state. HPT deformation was found to alter the surface behavior of the TiNi, which effectively reduced the Ni ion release and improved its biocompatibility.
MO‐D‐201B‐03: Evolutionary Trends in Indirect Detection X‐Ray Imager Technology Punctuated by Adaptive Innovation: From Active Matrix Flat‐Panel Imagers to Single‐Photon‐Counting Area Detectors
Authors: Antonuk L
Published: March 2014

From initial conception in the 1980's to widespread clinical implementation over the last decade, active matrix, flat‐panel imagers (AMFPIs) have ridden an incredible technological wave associated with the thin‐film electronics used in active matrix, liquid crystal displays. Despite the many benefits and advantages of contemporary AMFPIs, constraints imposed by their physical construction, performance and cost encourage further innovation. Some possible sources for such innovation originate from recent developments in thin‐film electronics driven by the display industry's need for ever‐larger area, brighter, less expensive, less power‐hungry, and flexible devices. In this presentation, the design and limitations of AMFPIs will be reviewed, a variety of conceivable technological directions for overcoming these limitations will be presented, and the potential capabilities of future x‐ray imagers will be discussed.

Learning Objectives:

1. Understand the basic principles, as well as the fundamental limits, of present‐day active matrix, flat‐panel x‐ray imagers

2. Understand the possible evolution of imager development

3. Understand the potential capabilities of future imagers
Modeling the effects of a single reflection on binaural speech intelligibility
Authors: Rennies Jan , Warzybok Anna , Brand Thomas , Kollmeier Birger
Published: March 2014

Recently the influence of delay and azimuth of a single speech reflection on speech reception thresholds (SRTs) was systematically investigated using frontal, diffuse, and lateral noise [Warzybok et al. (2013). J. Acoust. Soc. Am. 133, 269–282]. The experiments showed that the benefit of an early reflection was independent of its azimuth and mostly independent of noise type, but that the detrimental effect of a late reflection depended on its direction relative to the noise. This study tests if different extensions of a binaural speech intelligibility model can predict these data. The extensions differ in the order in which binaural processing and temporal integration of early reflections take place. Models employing a correction for the detrimental effects of reverberation on speech intelligibility after performing the binaural processing predict SRTs in symmetric masking conditions (frontal, diffuse), but cannot predict the measured interaction of temporal and spatial integration. In contrast, a model extension accounting for the distinction between useful and detrimental reflections before the binaural processing stage predicts the data with an overall R2 of 0.95. This indicates that any model framework predicting speech intelligibility in rooms should incorporate an interaction between binaural and temporal integration of reflections at a comparatively early stage.
The influence of material anisotropy on vibration at onset in a three-dimensional vocal fold model
Authors: Zhang Zhaoyan
Published: March 2014

Although vocal folds are known to be anisotropic, the influence of material anisotropy on vocal fold vibration remains largely unknown. Using a linear stability analysis, phonation onset characteristics were investigated in a three-dimensional anisotropic vocal fold model. The results showed that isotropic models had a tendency to vibrate in a swing-like motion, with vibration primarily along the superior-inferior direction. Anterior-posterior (AP) out-of-phase motion was also observed and large vocal fold vibration was confined to the middle third region along the AP length. In contrast, increasing anisotropy or increasing AP-transverse stiffness ratio suppressed this swing-like motion and allowed the vocal fold to vibrate in a more wave-like motion with strong medial-lateral motion over the entire medial surface. Increasing anisotropy also suppressed the AP out-of-phase motion, allowing the vocal fold to vibrate in phase along the entire AP length. Results also showed that such improvement in vibration pattern was the most effective with large anisotropy in the cover layer alone. These numerical predictions were consistent with previous experimental observations using self-oscillating physical models. It was further hypothesized that these differences may facilitate complete glottal closure in finite-amplitude vibration of anisotropic models as observed in recent experiments.
Whistle source levels of free-ranging bottlenose dolphins and Atlantic spotted dolphins in the Gulf of Mexico
Authors: Frankel Adam S. , Zeddies David , Simard Peter , Mann David
Published: March 2014

Whistles of bottlenose dolphins (Tursiops truncatus) and Atlantic spotted dolphins (Stenella frontalis) in the eastern Gulf of Mexico were recorded and measured with a calibrated towed hydrophone array. Surveys encountered groups of both bottlenose (N = 10) and spotted dolphins (N = 5). Analysis of those data produced 1695 bottlenose dolphin whistles and 1273 spotted dolphin whistles with a high signal-to-noise ratio. Whistle frequency metrics were lower in bottlenose than spotted dolphins, while whistle duration was longer in spotted dolphins, data that may help inform automatic classification algorithms. Source levels were estimated by determining the range and bearing of an individual dolphin from the array and then adding the predicted transmission loss to the calculated received level. The median bottlenose dolphin source level was 138 dB re 1μPa at 1 m with a range of 114–163 dB re 1μPa at 1 m. The median spotted dolphin source level was 138 dB re 1μPa at 1 m with a range of 115–163 dB re 1μPa at 1 m. These source level measurements, in conjunction with estimates of vocalization rates and transmission loss models, can be used to improve passive acoustically determined dolphin abundance estimates in the Gulf of Mexico.
Blue whale vocalizations recorded around New Zealand: 1964–2013
Authors: Miller Brian S. , Collins Kym , Barlow Jay , Calderan Susannah , Leaper Russell , McDonald Mark , Ensor Paul , Olson Paula A. , Olavarria Carlos , Double Michael C.
Published: March 2014

Previous underwater recordings made in New Zealand have identified a complex sequence of low frequency sounds that have been attributed to blue whales based on similarity to blue whale songs in other areas. Recordings of sounds with these characteristics were made opportunistically during the Southern Ocean Research Partnership's recent Antarctic Blue Whale Voyage. Detections of these sounds occurred all around the South Island of New Zealand during the voyage transits from Nelson, New Zealand to the Antarctic and return. By following acoustic bearings from directional sonobuoys, blue whales were visually detected and confirmed as the source of these sounds. These recordings, together with the historical recordings made northeast of New Zealand, indicate song types that persist over several decades and are indicative of the year-round presence of a population of blue whales that inhabits the waters around New Zealand. Measurements of the four-part vocalizations reveal that blue whale song in this region has changed slowly, but consistently over the past 50 years. The most intense units of these calls were detected as far south as 53°S, which represents a considerable range extension compared to the limited prior data on the spatial distribution of this population.
Principal pitch of frequency-modulated tones with asymmetrical modulation waveform: A comparison of models
Authors: Etchemendy Pablo E. , Eguia Manuel C. , Mesz Bruno
Published: March 2014

In this work, the overall perceived pitch (principal pitch) of pure tones modulated in frequency with an asymmetric waveform is studied. The dependence of the principal pitch on the degree of asymmetric modulation was obtained from a psychophysical experiment. The modulation waveform consisted of a flat portion of constant frequency and two linear segments forming a peak. Consistent with previous results, significant pitch shifts with respect to the time-averaged geometric mean were observed. The direction of the shifts was always toward the flat portion of the modulation. The results from the psychophysical experiment, along with those obtained from previously reported studies, were compared with the predictions of six models of pitch perception proposed in the literature. Even though no single model was able to predict accurately the perceived pitch for all experiments, there were two models that give robust predictions that are within the range of acceptable tuning of modulated tones for almost all the cases. Both models point to the existence of an underlying “stability sensitive” mechanism for the computation of pitch that gives more weight to the portion of the stimuli where the frequency is changing more slowly.
Data-driven matched field processing for Lamb wave structural health monitoring
Authors: Harley Joel B. , Moura José M. F.
Published: March 2014

Matched field processing is a model-based framework for localizing targets in complex propagation environments. In underwater acoustics, it has been extensively studied for improving localization performance in multimodal and multipath media. For guided wave structural health monitoring problems, matched field processing has not been widely applied but is an attractive option for damage localization due to equally complex propagation environments. Although effective, matched field processing is often challenging to implement because it requires accurate models of the propagation environment, and the optimization methods used to generate these models are often unreliable and computationally expensive. To address these obstacles, this paper introduces data-driven matched field processing, a framework to build models of multimodal propagation environments directly from measured data, and then use these models for localization. This paper presents the data-driven framework, analyzes its behavior under unmodeled multipath interference, and demonstrates its localization performance by distinguishing two nearby scatterers from experimental measurements of an aluminum plate. Compared with delay-based models that are commonly used in structural health monitoring, the data-driven matched field processing framework is shown to successfully localize two nearby scatterers with significantly smaller localization errors and finer resolutions.
The perceptual assimilation of Korean obstruents by native Mandarin listeners
Authors: Holliday Jeffrey J.
Published: March 2014

The current study reports the results of a perception experiment in which 20 naive native Mandarin listeners classified and rated the goodness of Korean stops /p, t, k, ph, th, kh, p*, t*, k*/, affricates /tɕ, tɕ*, tɕh/, and fricatives /sh, s*/ in terms of Mandarin segmental categories. It was found that listeners were sensitive to the voice onset time dimension of Korean stops and the presence of aspiration in Korean affricates, but Korean lenis and aspirated obstruents were generally assimilated to a single Mandarin category because the f0 cue differentiating them is not relevant to any Mandarin segmental contrast. The affricates were perceived as alveolopalatal and postalveolar more often than alveolar. The perception of fricatives was strongly influenced by vowel context, as the two fricatives were often perceived as different categories before /a/, but as the same category more often before /i/ and /u/. The results for the affricates and fricatives may be partly explained by Mandarin phonotactic constraints that prohibit alveolar and postalveolar consonants before /i/ and alveolopalatal consonants before /a/ or /u/.
Auditory gist: Recognition of very short sounds from timbre cues
Authors: Suied Clara , Agus Trevor R. , Thorpe Simon J. , Mesgarani Nima , Pressnitzer Daniel
Published: March 2014

Sounds such as the voice or musical instruments can be recognized on the basis of timbre alone. Here, sound recognition was investigated with severely reduced timbre cues. Short snippets of naturally recorded sounds were extracted from a large corpus. Listeners were asked to report a target category (e.g., sung voices) among other sounds (e.g., musical instruments). All sound categories covered the same pitch range, so the task had to be solved on timbre cues alone. The minimum duration for which performance was above chance was found to be short, on the order of a few milliseconds, with the best performance for voice targets. Performance was independent of pitch and was maintained when stimuli contained less than a full waveform cycle. Recognition was not generally better when the sound snippets were time-aligned with the sound onset compared to when they were extracted with a random starting time. Finally, performance did not depend on feedback or training, suggesting that the cues used by listeners in the artificial gating task were similar to those relevant for longer, more familiar sounds. The results show that timbre cues for sound recognition are available at a variety of time scales, including very short ones.
Impulse propagation over a complex site: A comparison of experimental results and numerical predictions
Authors: Dragna Didier , Blanc-Benon Philippe , Poisson Franck
Published: March 2014

Results from outdoor acoustic measurements performed in a railway site near Reims in France in May 2010 are compared to those obtained from a finite-difference time-domain solver of the linearized Euler equations. During the experiments, the ground profile and the different ground surface impedances were determined. Meteorological measurements were also performed to deduce mean vertical profiles of wind and temperature. An alarm pistol was used as a source of impulse signals and three microphones were located along a propagation path. The various measured parameters are introduced as input data into the numerical solver. In the frequency domain, the numerical results are in good accordance with the measurements up to a frequency of 2 kHz. In the time domain, except a time shift, the predicted waveforms match the measured waveforms with a close agreement.
Prediction of consonant recognition in quiet for listeners with normal and impaired hearing using an auditory model
Authors: Jürgens Tim , Ewert Stephan D. , Kollmeier Birger , Brand Thomas
Published: March 2014

Consonant recognition was assessed in normal-hearing (NH) and hearing-impaired (HI) listeners in quiet as a function of speech level using a nonsense logatome test. Average recognition scores were analyzed and compared to recognition scores of a speech recognition model. In contrast to commonly used spectral speech recognition models operating on long-term spectra, a “microscopic” model operating in the time domain was used. Variations of the model (accounting for hearing impairment) and different model parameters (reflecting cochlear compression) were tested. Using these model variations this study examined whether speech recognition performance in quiet is affected by changes in cochlear compression, namely, a linearization, which is often observed in HI listeners. Consonant recognition scores for HI listeners were poorer than for NH listeners. The model accurately predicted the speech reception thresholds of the NH and most HI listeners. A partial linearization of the cochlear compression in the auditory model, while keeping audibility constant, produced higher recognition scores and improved the prediction accuracy. However, including listener-specific information about the exact form of the cochlear compression did not improve the prediction further.
Diversity-based acoustic communication with a glider in deep water
Authors: Song H. C. , Howe Bruce M. , Brown Michael G. , Andrew Rex K.
Published: March 2014

The primary use of underwater gliders is to collect oceanographic data within the water column and periodically relay the data at the surface via a satellite connection. In summer 2006, a Seaglider equipped with an acoustic recording system received transmissions from a broadband acoustic source centered at 75 Hz deployed on the bottom off Kauai, Hawaii, while moving away from the source at ranges up to ∼200 km in deep water and diving up to 1000-m depth. The transmitted signal was an m-sequence that can be treated as a binary-phase shift-keying communication signal. In this letter multiple receptions are exploited (i.e., diversity combining) to demonstrate the feasibility of using the glider as a mobile communication gateway.
Characterizing the Speech Reception Threshold in hearing-impaired listeners in relation to masker type and masker level
Authors: Rhebergen Koenraad S. , Pool Ruben E. , Dreschler Wouter A.
Published: March 2014

The Speech Reception Threshold [SRT, (dB SNR)] is often used as an outcome measure to quantify the acuity for speech perception in noise. The majority of studies observe speech intelligibility in noise at a fixed noise level. However, the observed SNR might be an ambiguous outcome measure because it is dependent on the sensation level (SL) of the noise in the case of a non-stationary noise. Due to their higher thresholds, hearing-impaired listeners are usually tested at a different SL compared to normal-hearing listeners. Therefore, the observed SNR “itself” might not be a robust outcome measure to characterize the differences in performance between normal-hearing and hearing-impaired listeners, within and between different studies. In this paper, the SRTs are measured at a fixed absolute noise level (80 dBA) and at a fixed SL (25 dB). The results are discussed and described with an extension to the SRT model of Plomp [(1986). “A signal-to-noise ratio model for the speech-receptionthreshold of the hearing-impaired,” J. Speech Hear. Res. 29, 146–154] and the Extended Speech Intelligibility Index. In addition, two alternative outcome measures are proposed which are, in contrast to the SNR, independent of the noise level. These outcome measures are able to characterize the SRT performance in fluctuating noise in a more uniform and unambiguous way.
Determination of the acoustoelastic coefficient for surface acoustic waves using dynamic acoustoelastography: An alternative to static strain
Authors: Ellwood R. , Stratoudaki T. , Sharples S. D. , Clark M. , Somekh M. G.
Published: March 2014

The third-order elastic constants of a material are believed to be sensitive to residual stress, fatigue, and creep damage. The acoustoelastic coefficient is directly related to these third-order elastic constants. Several techniques have been developed to monitor the acoustoelastic coefficient using ultrasound. In this article, two techniques to impose stress on a sample are compared, one using the classical method of applying a static strain using a bending jig and the other applying a dynamic stress due to the presence of an acoustic wave. Results on aluminum samples are compared. Both techniques are found to produce similar values for the acoustoelastic coefficient. The dynamic strain technique however has the advantages that it can be applied to large, real world components, in situ, while ensuring the measurement takes place in the nondestructive, elastic regime.
Multichannel instantaneous frequency analysis of ultrasound propagating in cancellous bone
Authors: Nagatani Yoshiki , Tachibana Ryosuke O.
Published: March 2014

An ultrasonic pulse propagating in cancellous bone can be separated into two waves depending on the condition of the specimen. These two waves, which are called the fast wave and the slow wave, provide important information for the diagnosis of osteoporosis. The present study proposes to utilize a signal processing method that extracts the instantaneous frequency (IF) of waveforms from multiple spectral channels. The instantaneous frequency was expected to be able to show detailed time-frequency properties of ultrasonic waves being transmitted through cancellous bone. The employed method, termed the multichannel instantaneous frequency (MCIF) method, showed robustness against background noise as compared to the IF that was directly derived from the original waveform. The extracted IF revealed that the frequency of the fast wave was affected by both the propagation distance within the specimen and the bone density, independently. On the other hand, the alternation of the center frequency of the originally transmitted wave did not produce proportional changes in the extracted IF values of the fast waves, suggesting that the fast wave IF mainly reflected the thickness of the specimens. These findings may provide the possibility of obtaining a more precise diagnosis of osteoporosis.
Experimental study on inter-particle acoustic forces
Authors: Garcia-Sabaté Anna , Castro Angélica , Hoyos Mauricio , González-Cinca Ricard
Published: March 2014

A method for the experimental measurement of inter-particle forces (secondary Bjerknes force) generated by the action of an acoustic field in a resonator micro-channel is presented. The acoustic radiation force created by an ultrasonic standing wave moves suspended particles towards the pressure nodes and the acoustic pressure induces particle volume oscillations. Once particles are in the levitation plane, transverse and secondary Bjerknes forces become important. Experiments were carried out in a resonator filled with a suspension composed of water and latex particles of different size (5–15 μm) at different concentrations. Ultrasound was generated by means of a 2.5 MHz nominal frequency transducer. For the first time the acoustic force generated by oscillating particles acting on other particles has been measured, and the critical interaction distance in various cases has been determined. Inter-particle forces on the order of 10−14 N have been measured by using this method.
Influence of shell compressibility on the ultrasonic properties of polydispersed suspensions of nanometric encapsulated droplets
Authors: Guédra Matthieu , Valier-Brasier Tony , Conoir Jean-Marc , Coulouvrat François , Astafyeva Ksenia , Thomas Jean-Louis
Published: March 2014

Liquid droplets of nanometric size encapsulated by a polymer shell are envisioned for targeted drug delivery in therapeutic applications. Unlike standard micrometric gas-filled contrast agents used for medical imaging, these particles present a thick shell and a weakly compressible core. Hence, their dynamical behavior may be out of the range of validity of the models available for the description of encapsulated bubbles. In the present paper, a model for the ultrasound dispersion and absorption in a suspension of nanodroplets is proposed, accounting for both dilatational and translational motions of the particle. The radial motion is modeled by a generalized Rayleigh–Plesset-like equation which takes into account the compressibility of the viscoelastic shell, as well as the one of the core. The effect of the polydispersity of particles in size and shell thickness is introduced in the coupled balance equations which govern the motion of the particles in the surrounding fluid. Both effects of shell compressibility and polydispersity are quantified through the dispersion and absorption curves obtained on a wide ultrasonic frequency range. Finally, some results for larger gas-filled particles are also provided, revealing the limit of the role of the shell compressibility.
Altitudinal Changes in Malaria Incidence in Highlands of Ethiopia and Colombia
Authors: Siraj A. S. , Santos-Vega M. , Bouma M. J. , Yadeta D. , Carrascal D. Ruiz , Pascual M.
Published: March 2014

Altitude Sickness

Whether the incidence of malaria will be (or has been) affected by the warming climate is poorly resolved. Global-scale analyses are fraught with technical difficulties, including problems with separating out changes resulting from destruction of mosquito habitat, insecticide use, and antimalarial drug use from multidecadal trends in climate change.

Siraj
et al.

(p.
1154
) performed parallel analyses of highland malaria in Ethiopia and Colombia to ask whether interannual changes in temperature could explain variation in malaria incidence with altitude. Modeling the data confirmed that malaria moves up in elevation in warmer years and allowed estimates of how many more millions of cases could be expected in tropical highland areas if the mean temperature increased by 1° to 3°C.
Why Should We Care About Temporary Waterways?
Authors: Acuña V. , Datry T. , Marshall J. , Barceló D. , Dahm C. N. , Ginebreda A. , McGregor G. , Sabater S. , Tockner K. , Palmer M. A.
Published: March 2014

Intermittently flowing streams and rivers should be recognized, afforded protection, and better managed.
Crystal Structures of Nucleotide-Free and Glutathione-Bound Mitochondrial ABC Transporter Atm1
Authors: Srinivasan Vasundara , Pierik Antonio J. , Lill Roland
Published: March 2014

Crossing the Membrane

Adenosine triphosphate (ATP)–binding cassette (ABC) transporters couple ATP hydrolysis to the translocation of a wide variety of substrates across cell membranes.

Srinivasan
et al.

(p.
1137
) describe the structure of a yeast mitochondrial transporter involved in Fe-S protein biogenesis. The structure reveals bound glutathione, which suggests that glutathione is part of the translocated substrate.

J. Y. Lee
et al.

(p.
1133
) describe the structure of a bacterial ABC transporter that confers protection against silver and mercury. This protein also binds glutathione derivatives. The structure provides insight into how ligand interactions are coupled to ATP hydrolysis.
Cutting-Edge Techniques Used for the Structural Investigation of Single Crystals
Authors: Howard Judith A. K. , Probert Michael R.
Published: March 2014

X-ray crystallography has become the leading technique for studying the structure of matter at the atomic and molecular level. Today it underpins all sciences and is widely applied in industry. It is essential in the development of new materials. The technique is very powerful, and the range of materials that can be studied expands as new technologies evolve and are applied in innovative ways to structure solution. It is now possible to record vast amounts of diffraction data in seconds electronically, whereas it took days and months by photographic methods 30 to 40 years ago. Single crystals can be created in various ways; they can be produced from compounds that are liquids or gases at room temperature, and complete molecular structures can be presented within minutes. This short review presents recent developments that are appropriate to the single-crystal x-ray studies of chemical and materials sciences.
Combating Evolution to Fight Disease
Authors: Rosenberg Susan M. , Queitsch Christine
Published: March 2014

Molecular mechanisms that generate biological diversity are rewriting ideas about how evolution proceeds, with implications for treating disease.
Epistasis and Allele Specificity in the Emergence of a Stable Polymorphism in
Escherichia coli
Authors: Plucain Jessica , Hindré Thomas , Le Gac Mickaël , Tenaillon Olivier , Cruveiller Stéphane , Médigue Claudine , Leiby Nicholas , Harcombe William R. , Marx Christopher J. , Lenski Richard E. , Schneider Dominique
Published: March 2014

Serial Mutation

Mutations that affect gene function and, ultimately, the phenotype of an organism are grist to the mill of evolution. While examining the genetic basis for a stable polymorphism observed in bacteria during a long-term mutation experiment,

Plucain
et al.

(p.
1366
, published online 6 March) identified three specific, successive mutational events exhibiting synergistic epistatic and frequency-dependent interactions that enabled one lineage to invade the other and to be maintained. Thus, a series of specific mutations conferred the invasion phenotype and allowed the use of novel resources only when all mutations were present.
The Secret Garden—Epigenetic Alleles Underlie Complex Traits
Authors: Schmitz Robert J.
Published: March 2014

In the plant
Arabidopsis thaliana
, epigenetic variation, like genetic change, is potentially a substrate for Darwinian evolution.

[Also see Report by

Cortijo
et al.

]
Gently Does It
Authors: Service Robert F.
Published: March 2014

A technique for crystallizing fragile biomolecules without disrupting them is helping researchers probe the structures of some of the body's most important but elusive proteins: those that usher other chemicals through the cell membrane.
Complete Genome Sequence of a Brucella ceti ST26 Strain Isolated from a Striped Dolphin (
Stenella coeruleoalba
) on the Coast of Italy
Authors: Ancora Massimo , Marcacci Maurilia , Orsini Massimiliano , Zilli Katiuscia , Di Giannatale Elisabetta , Garofolo Giuliano , Cammà Cesare
Published: March 2014

Brucella
spp. are important pathogens affecting a wide range of terrestrial and aquatic animals. We report the complete and annotated genome sequence of
Brucella ceti
ST26 strain TE10759-12, isolated from a striped dolphin (
Stenella coeruleoalba
) stranded along the Italian shoreline in March of 2012.
Draft Genome Sequence of
Commensalibacter papalotli
MX01, a Symbiont Identified from the Guts of Overwintering Monarch Butterflies
Authors: Servín-Garcidueñas Luis E. , Sánchez-Quinto Andrés , Martínez-Romero Esperanza
Published: March 2014

We report the draft genome sequence of
Commensalibacter papalotli
strain MX01, isolated from the intestines of an overwintering monarch butterfly. The 2,332,652-bp AT-biased genome of
C. papalotli
MX01 is the smallest genome for a member of the
Acetobacteraceae
family and provides the first evidence of plasmids in
Commensalibacter
.
Draft Genome Sequence of the Antitrypanosomally Active Sponge-Associated Bacterium
Actinokineospora
sp. Strain EG49
Authors: Harjes Janno , Ryu Taewoo , Abdelmohsen Usama Ramadan , Moitinho-Silva Lucas , Horn Hannes , Ravasi Timothy , Hentschel Ute
Published: March 2014

The marine sponge-associated bacterium
Actinokineospora
sp. strain EG49 produces the antitrypanosomal angucycline-like compound actinosporin A. The draft genome of
Actinokineospora
sp. EG49 has a size of 7.5 megabases and a GC content of 72.8% and contains 6,629 protein-coding sequences (CDS). antiSMASH predicted 996 genes residing in 36 secondary metabolite gene clusters.
Draft Genome Sequence of a Methicillin-Resistant Staphylococcus aureus ST1413 Strain for Studying Genetic Mechanisms of Antibiotic Resistance
Authors: Marasa Bernard S. , Revollo Javier , Iram Saira , Sung Kidon , Xu Joshua , Khan Saeed
Published: March 2014

Here we report the whole draft genome sequence of a methicillin-resistant
Staphylococcus aureus
ST1413 strain. Determining the distribution and arrangement of various genes associated with drug resistance, toxicity, and diseases will enhance our understanding about its adaptability to thrive in different ecological niches and help in the development of effective treatments for enterotoxigenic staphylococcal infections.
Health assessment of commercial drivers: a meta-narrative systematic review
Authors: Abu Dabrh Abd Moain , Firwana Belal , Cowl Clayton T , Steinkraus Lawrence W , Prokop Larry J , Murad Mohammad Hassan
Published: March 2014

Background

Motor vehicle accidents associated with commercial driving are an important cause of occupational death and impact public safety.

Objectives

We summarise the evidence regarding the type, prevalence and impact of medical conditions discovered during health assessment of commercial drivers.

Evidence review

We conducted a systematic review of multiple electronic databases and made a manual search for relevant studies that enrolled commercial drivers in any country and reported the outcomes of health assessment carried out in the context of commercial driving through November 2012. Data were extracted by a pair of independent reviewers and synthesised using a metanarrative approach.

Results

We identified 32 studies of moderate methodological quality enrolling 151 644 commercial drivers (98% men). The prevalence of multiple health conditions was high (sleep disorders 19%, diabetes 33%, hypertension 23% and obesity 45%). Some conditions, such as sleep disorders and obesity, were linked to increased risk of crashes. Evidence on several other highly relevant medical conditions was lacking. Cost-effectiveness data were sparse.

Conclusions

Several medical conditions are highly prevalent in commercial drivers and can be associated with increased risk of crashes, thus providing a rationale for health assessment of commercial drivers.
Smoking cessation in adults with diabetes: a systematic review and meta-analysis of data from randomised controlled trials
Authors: Nagrebetsky Alexander , Brettell Rachel , Roberts Nia , Farmer Andrew
Published: March 2014

Objectives

To evaluate the effects of more intensive smoking cessation interventions compared to less intensive interventions on smoking cessation in people with type 1 or type 2 diabetes.

Design

A systematic review and meta-analysis of randomised trials of smoking cessation interventions was conducted. Electronic searches were carried out on the following databases: MEDLINE, EMBASE, CINAHL and PsycINFO to September 2013. Searches were supplemented by review of trial registries and references from identified trials. Citations and full-text articles were screened by two reviewers. A random-effect Mantel-Haenszel model was used to pool data.

Setting

Primary, secondary and tertiary care.

Participants

Adults with type 1 or type 2 diabetes.

Interventions

Smoking cessation interventions or medication (more intensive interventions) compared to usual care, counselling or optional medication (less intensive interventions).

Outcome measures

Biochemically verified smoking cessation was the primary outcome. Secondary outcomes were adverse events and effects on glycaemic control. We also carried out a pooled analysis of self-reported smoking cessation outcomes.

Results

We screened 1783 citations and reviewed seven articles reporting eight trials in 872 participants. All trials were of 6 months duration. Three trials included pharmacotherapy for smoking cessation. The risk ratio of biochemically verified smoking cessation was 1.32 (95% CI 0.23 to 7.43) for the more intensive interventions compared to less intensive interventions with significant heterogeneity (I2=76%). Only one trial reported measures of glycaemic control.

Conclusions

There is an absence of evidence of efficacy for more intensive smoking cessation interventions in people with diabetes. The more intensive strategies tested in trials to date include interventions used in the general population, adding in diabetes-specific education about increased risk. Future research should focus on multicomponent smoking cessation interventions carried out over a period of at least 1 year, and also assess impact on glycaemic control.
Assessing communication quality of consultations in primary care: initial reliability of the Global Consultation Rating Scale, based on the Calgary-Cambridge Guide to the Medical Interview
Authors: Burt Jenni , Abel Gary , Elmore Natasha , Campbell John , Roland Martin , Benson John , Silverman Jonathan
Published: March 2014

Objectives

To investigate initial reliability of the Global Consultation Rating Scale (GCRS: an instrument to assess the effectiveness of communication across an entire doctor–patient consultation, based on the Calgary-Cambridge guide to the medical interview), in simulated patient consultations.

Design

Multiple ratings of simulated general practitioner (GP)–patient consultations by trained GP evaluators.

Setting

UK primary care.

Participants

21 GPs and six trained GP evaluators.

Outcome measures

GCRS score.

Methods

6 GP raters used GCRS to rate randomly assigned video recordings of GP consultations with simulated patients. Each of the 42 consultations was rated separately by four raters. We considered whether a fixed difference between scores had the same meaning at all levels of performance. We then examined the reliability of GCRS using mixed linear regression models. We augmented our regression model to also examine whether there were systematic biases between the scores given by different raters and to look for possible order effects.

Results

Assessing the communication quality of individual consultations, GCRS achieved a reliability of 0.73 (95% CI 0.44 to 0.79) for two raters, 0.80 (0.54 to 0.85) for three and 0.85 (0.61 to 0.88) for four. We found an average difference of 1.65 (on a 0–10 scale) in the scores given by the least and most generous raters: adjusting for this evaluator bias increased reliability to 0.78 (0.53 to 0.83) for two raters; 0.85 (0.63 to 0.88) for three and 0.88 (0.69 to 0.91) for four. There were considerable order effects, with later consultations (after 15–20 ratings) receiving, on average, scores more than one point higher on a 0–10 scale.

Conclusions

GCRS shows good reliability with three raters assessing each consultation. We are currently developing the scale further by assessing a large sample of real-world consultations.
Redesigning care to meet national recommendation of four or more yearly clinic visits in patients with cystic fibrosis
Authors: Berlinski A , Chambers M J , Willis L , Homa K , Com G
Published: March 2014

Cystic fibrosis (CF) is a chronic disease requiring patients to have frequent specialty healthcare visits to delay progression of lung disease, prevent and treat failure to thrive and initiate early interventions to prevent acute illness and complications. The CF Foundation recommends that patients have visits with the CF care team at least every 3 months. During participation in the CF Foundation Learning and Leadership Collaborative IV, the CF team at Arkansas Children's Hospital initiated quality improvement work with the aim to increase the percentage of patients attending clinic four or more times a year from 35% in 2004 and 56% in 2005 (CF Foundation Registry data) to 90% or greater. We redesigned our scheduling system, rescheduled missed patient appointments in a timely fashion and created a process to monitor attendance. This quality improvement work led to a sustained increase in the percentage of patients attending clinic visits four or more times a year reaching our goal of 90% in 2012. Improvements were also noted in the number of patients with body mass index/weight-for-length centile of 25 or greater, which could be related to more frequent clinic attendance.
The impact of re-education of airway clearance techniques (REACT) on adherence and pulmonary function in patients with cystic fibrosis
Authors: Zanni Robert L , Sembrano Eduardo U , Du Doantrang T , Marra Bridget , Bantang Ronald
Published: March 2014

Background

Our centre's median forced expiratory volume in one second (FEV1) reported in the 2005 Cystic Fibrosis (CF) Foundation Patient Registry was below the national median. The focus of our quality improvement initiative was to improve lung function through re-education of airway clearance techniques (REACT).

Aim

The global aim was to improve the median FEV1in our patients. The specific aim was to encourage adherence to airway clearance techniques (ACT). To achieve these goals we implemented the REACT programme for patients.

Methods

Educational sessions introduced the concept of improving clinical outcomes and the importance of airway clearance in achieving optimal lung function. The REACT programme utilised an anonymous survey, in-clinic questionnaire and ACT demonstration to assess knowledge, practices and barriers to ACT. Patients were then categorised as non-adherent or adherent with correct or incorrect technique. Improper techniques were corrected. All patients were re-educated on the rationale for ACT.

Results

Our surveys revealed that 43% of patients had barriers to ACT and 53% were non-adherent. Following implementation of REACT, median FEV1increased from 84% to 92% (national median 91–94%) from 2005 to 2010 for patients aged 6–17. For patients 18 and older, median FEV1increased from 56% to 64% (national median 62–65%) from 2005 to 2010.

Conclusions

By introducing a programme focused on technique and adherence, we were able to improve median FEV1in patients with CF. Sustained improvement of FEV1was accomplished by continued use of the REACT programme.