bluuebunny/crossref_metadata_2025 huggingface dataset:
A Multilevel Modeling Framework to Study Hepatic Perfusion Characteristics in Case of Liver Cirrhosis
Authors: Peeters Geert , Debbaut Charlotte , Cornillie Pieter , De Schryver Thomas , Monbaliu Diethard , Laleman Wim , Segers Patrick
Published: December 2014

Liver cirrhosis represents the end-stage of different liver disorders, progressively affecting hepatic architecture, hemodynamics, and function. Morphologically, cirrhosis is characterized by diffuse fibrosis, the conversion of normal liver architecture into structurally abnormal regenerative nodules and the formation of an abundant vascular network. To date, the vascular remodeling and altered hemodynamics due to cirrhosis are still poorly understood, even though they seem to play a pivotal role in cirrhogenesis. This study aims to determine the perfusion characteristics of the cirrhotic circulation using a multilevel modeling approach including computational fluid dynamics (CFD) simulations. Vascular corrosion casting and multilevel micro-CT imaging of a single human cirrhotic liver generated detailed datasets of the hepatic circulation, including typical pathological characteristics of cirrhosis such as shunt vessels and dilated sinusoids. Image processing resulted in anatomically correct 3D reconstructions of the microvasculature up to a diameter of about 500 μm. Subsequently, two cubic samples (150 × 150 × 150 μm3) were virtually dissected from vascularized zones in between regenerative nodules and applied for CFD simulations to study the altered cirrhotic microperfusion and permeability. Additionally, a conceptual 3D model of the cirrhotic macrocirculation was developed to reveal the hemodynamic impact of regenerative nodules. Our results illustrate that the cirrhotic microcirculation is characterized by an anisotropic permeability showing the highest value in the direction parallel to the central vein (kd,zz = 1.68 × 10−13 m2 and kd,zz = 7.79 × 10−13 m2 for sample 1 and 2, respectively) and lower values in the circumferential (kd,ϑϑ = 5.78 × 10−14 m2 and kd,ϑϑ = 5.65 × 10−13 m2 for sample 1 and 2, respectively) and radial (kd,rr = 9.87 × 10−14 m2 and kd,rr = 5.13 × 10−13 m2 for sample 1 and 2, respectively) direction. Overall, the observed permeabilities are markedly higher compared to a normal liver, implying a locally decreased intrahepatic vascular resistance (IVR) probably due to local compensation mechanisms (dilated sinusoids and shunt vessels). These counteract the IVR increase caused by the presence of regenerative nodules and dynamic contraction mechanisms (e.g., stellate cells, NO-concentration, etc.). Our conceptual 3D model of the cirrhotic macrocirculation indicates that regenerative nodules severely increase the IVR beyond about 65 vol. % of regenerative nodules. Numerical modeling allows quantifying perfusion characteristics of the cirrhotic macro- and microcirculation, i.e., the effect of regenerative nodules and compensation mechanisms such as dilated sinusoids and shunt vessels. Future research will focus on the development of models to study time-dependent degenerative adaptation of the cirrhotic macro- and microcirculation.
Amplitudes Decay in Different Kinds of Nonlinear Oscillators
Authors: Al-Shudeifat Mohammad A.
Published: December 2014

A transformation is employed to obtain expressions for the decay of the displacement, the velocity, and the energy for various forms of nonlinear oscillators. The equation of motion of the nonlinear oscillator is transformed into a first-order decay term plus an energy term, where this transformed equation can be decoupled into a set of two analytically solvable equations. The decoupled equations can be solved for the decay formulas. Unlike other methods in the literature, this transformation method is directly applied to the equation of motion, and an approximate solution is not required to be known a priori. The method is first applied to a purely nonlinear oscillator with a non-negative, real-power restoring force to obtain the decay formulas. These decay formulas are found to behave similarly to those of a linear oscillator. In addition, these formulas are employed to obtain an accurate formula for the frequency decay. Based on this result, the exact frequency formula given in the literature for this oscillator is generalized by substituting the initial values of the envelopes for the actual initial conditions. By this modification, the formulas for the initial and time-varying frequencies become valid for any combination of the initial displacement and velocity. Furthermore, a generalized nonlinear oscillator for which the transformation is always valid is introduced. From this generalized oscillator, the proposed transformation is applied to analyze various types of oscillators.
Design of Planar Multi-Degree-of-Freedom Morphing Mechanisms
Authors: Funke Lawrence W. , Schmiedeler James P. , Zhao Kai
Published: December 2014

This paper seeks to advance the design of planar multiloop shape-changing mechanisms used in a variety of applications, such as morphing extrusion dies and airfoils. The presence of defects is a limiting factor in finding suitable single-degree-of-freedom (DOF) morphing mechanisms, particularly when the number of shapes to achieve is large and/or the changes among those shapes are significant. This paper presents methods of designing multi-DOF mechanisms to expand the design space in which to find suitable defect-free solutions. The primary method uses a building block approach with Assur group of class II chains, similar to the current 1-DOF synthesis procedure. It is compared to both the 1-DOF procedure and an alternative multi-DOF procedure that generates mechanisms with single-DOF subchains. In all cases, a genetic algorithm is employed to search the design space. Two example problems involving four prescribed shapes demonstrate that mechanisms exhibiting superior shape matching are achieved with the primary multi-DOF procedure, as compared to the other two procedures.
Development and Validation of a Dynamic Model of Magneto-Active Elastomer Actuation of the Origami Waterbomb Base
Authors: Bowen Landen , Springsteen Kara , Feldstein Hannah , Frecker Mary , Simpson Timothy W. , von Lockette Paris
Published: December 2014

Of special interest in the growing field of origami engineering is self-folding, wherein a material is able to fold itself in response to an applied field. In order to simulate the effect of active materials on an origami-inspired design, a dynamic model is needed. Ideally, the model would be an aid in determining how much active material is needed and where it should be placed to actuate the model to the desired position(s). A dynamic model of the origami waterbomb base, a well-known and foundational origami mechanism, is developed using adams 2014, a commercial multibody dynamics software package. Creases are approximated as torsion springs with both stiffness and damping. The stiffness of an origami crease is calculated, and the dynamic model is verified using the waterbomb. An approximation of the torque produced by magneto-active elastomers (MAEs) is calculated and is used to simulate MAE-actuated self-folding of the waterbomb. Experimental validation of the self-folding waterbomb model is performed, verifying that the dynamic model is capable of accurate simulation of the fold angles.
Residual stress modeling of density modulated silicon thin films using finite element analysis
Authors: Citirik Erman , Demirkan Taha , Karabacak Tansel
Published: December 2014

Density modulated thin films offer a compliant property that can reduce residual stress, which typically originate during the growth of thin films. Lower residual stress improves adhesion properties of the film with reduced buckling or delamination, and therefore leads to more durable coatings. In this study, finite element analysis (FEA) was employed to simulate the residual stresses developed in density modulated silicon (Si) thin films, which incorporate alternating low and high density layers. The main focus of this investigation is not developing new FEA algorithms but to verify the impact of density modulated layers quantitatively using computational methods. Hence, verification of a predicted stress reduction enhances the current understanding of the mechanics of density modulated layered thin films. FEA simulation results reveal that low density layers act compliant and result in significant reduction in film stress especially at the interface with the substrate. For example, maximum stress at the film/substrate interface, which is in the substrate, was reduced from 2897 MPa down to 2432 MPa by simply adding a 100 nm thick density-modulated low-density Si layer in between a 300 μm thick Si wafer substrate and 1 μm thick conventional high density Si film, which makes the reduction percentage of the maximum stress about 16%.
Optimal source placement for sound zone reproduction with first order reflections
Authors: Olik Marek , Jackson Philip J. B. , Coleman Philip , Pedersen Jan Abildgaard
Published: December 2014

The problem of delivering personal audio content to listeners sharing the same acoustic space has recently attracted attention. It has been shown that a perceptually acceptable level of acoustic separation between the listening zones is difficult to achieve with active control in non-anechoic conditions. A common problem of strong first order reflections has not been examined in detail for systems with practical constraints. Acoustic contrast maximization combined with optimization of source positions is identified as a potentially effective control strategy when strong individual reflections occur. An analytic study is carried out to describe the relationship between the performance of a 2 × 2 (two sources and two control sensors) system and its geometry in a single-reflection scenario. The expression for acoustic contrast is used to formulate guidelines for optimizing source positions, based on three distinct techniques: Null-Split, Far-Align, and Near-Align. The applicability of the techniques to larger systems with up to two reflections is demonstrated using numerical optimization. Simulation results show that optimized systems produce higher acoustic contrast than non-optimized source arrangements and an alternative method for reducing the impact of reflections (sound power minimization).
Derivation and implementation of the boundary integral formula for the convective acoustic wave equation in time domain
Authors: Lee Yong Woo , Lee Duck Joo
Published: December 2014

Kirchhoff's formula for the convective wave equation is derived using the generalized function theory. The generalized convective wave equation for a stationary surface is obtained, and the integral formulation, the convective Kirchhoff's formula, is derived. The formula has a similar form to the classical Kirchhoff's formula, but an additional term appears due to a moving medium effect. For convenience, the additional term is manipulated to a final form as the classical Kirchhoff's formula. The frequency domain boundary integral can be obtained from the current time domain boundary integral form. The derived formula is verified by comparison with the analytic solution of source in the uniform flow. The formula is also utilized as a boundary integral equation. Time domain boundary element method (BEM) analysis using the boundary integral equation is conducted, and the results show good agreement with the analytical solution. The formula derived here can be useful for sound radiation and scattering by arbitrary bodies in a moving medium in the time domain.
Thermo-elastic multiple scattering in random dispersions of spherical scatterers
Authors: Pinfield Valerie J.
Published: December 2014

Ultrasonic monitoring of concentrated suspensions and emulsions is limited in concentration range due to the inaccuracy of the multiple scattering models currently used to interpret measurements. This paper presents the development of a model for the additional multiple scattering caused by mode conversion to/from thermal waves. These effects are believed to cause significant deviation from established models for emulsions at high concentration, or small particle size, at low frequency. The relevant additional scattering coefficients (transition factors) are developed, in numerical and analytical form, together with the modification to the effective wavenumber. Calculations have been carried out for a bromohexadecane-in-water emulsion to demonstrate the frequency-dependence of the scattering coefficients, and the effective speed and attenuation.
Metamaterial buffer for broadband non-resonant impedance matching of obliquely incident acoustic waves
Authors: Fleury Romain , Alù Andrea
Published: December 2014

Broadband impedance matching and zero reflection of acoustic waves at a planar interface between two natural materials is a rare phenomenon, unlike its optical counterpart, frequently observed for polarized light incident at the Brewster angle. In this article, it is shown that, by inserting a metamaterial layer between two acoustic materials with different impedance, it is possible to artificially realize an extremely broadband Brewster-like acoustic intromission angle window, in which energy is totally transmitted from one natural medium to the other. The metamaterial buffer, composed of acoustically hard materials with subwavelength tapered apertures, provides an interesting way to match the impedances of two media in a broadband fashion, different from traditional methods like quarter-wave matching or Fabry-Pérot resonances, inherently narrowband due to their resonant nature. This phenomenon may be interesting for a variety of applications including energy harvesting, acoustic imaging, ultrasonic transducer technology, and noise control.
Auditory sensitivity of seals and sea lions in complex listening scenarios
Authors: Cunningham Kane A. , Southall Brandon L. , Reichmuth Colleen
Published: December 2014

Standard audiometric data, such as audiograms and critical ratios, are often used to inform marine mammal noise-exposure criteria. However, these measurements are obtained using simple, artificial stimuli—i.e., pure tones and flat-spectrum noise—while natural sounds typically have more complex structure. In this study, detection thresholds for complex signals were measured in (I) quiet and (II) masked conditions for one California sea lion (Zalophus californianus) and one harbor seal (Phoca vitulina). In Experiment I, detection thresholds in quiet conditions were obtained for complex signals designed to isolate three common features of natural sounds: Frequency modulation, amplitude modulation, and harmonic structure. In Experiment II, detection thresholds were obtained for the same complex signals embedded in two types of masking noise: Synthetic flat-spectrum noise and recorded shipping noise. To evaluate how accurately standard hearing data predict detection of complex sounds, the results of Experiments I and II were compared to predictions based on subject audiograms and critical ratios combined with a basic hearing model. Both subjects exhibited greater-than-predicted sensitivity to harmonic signals in quiet and masked conditions, as well as to frequency-modulated signals in masked conditions. These differences indicate that the complex features of naturally occurring sounds enhance detectability relative to simple stimuli.
Modular feed-forward active noise control units for ventilation ducts
Authors: Gardonio P. , Rohlfing J.
Published: December 2014

This paper presents theoretical and experimental work on feed-forward active noise control for a ventilation duct. In particular three single channel control arrangements are investigated: (a) A classical widespread-mid-span configuration, where the control loudspeakers are located approximately half way through the duct and the reference and error microphones are placed close to inlet and outlet duct sections, respectively; (b) a compact-mid-span configuration, where both the reference and error microphones are moved close to the control loudspeakers to form a self-contained control unit, and (c) a compact-outlet configuration where the self-contained control unit is moved to the duct outlet. The two compact configurations offer self-evident practical installation and operation advantages. Moreover, the paper shows that they are characterized by much simpler control filters, which can be effectively implemented on modern audio digital signal processing boards and produce similar control performance to the classical widespread configuration.
Optimizing frequency-to-electrode allocation for individual cochlear implant users
Authors: Grasmeder Mary L. , Verschuur Carl A. , Batty Vincent B.
Published: December 2014

Individual adjustment of frequency-to-electrode assignment in cochlear implants (CIs) may potentially improve speech perception outcomes. Twelve adult CI users were recruited for an experiment, in which frequency maps were adjusted using insertion angles estimated from post-operative x rays; results were analyzed for ten participants with good quality x rays. The allocations were a mapping to the Greenwood function, a compressed map limited to the area containing spiral ganglion (SG) cells, a reduced frequency range map (RFR), and participants' clinical maps. A trial period of at least six weeks was given for the clinical, Greenwood, and SG maps although participants could return to their clinical map if they wished. Performance with the Greenwood map was poor for both sentence and vowel perception and correlated with insertion angle; performance with the SG map was poorer than for the clinical map. The RFR map was significantly better than the clinical map for three participants, for sentence perception, but worse for three others. Those with improved performance had relatively deep insertions and poor electrode discrimination ability for apical electrodes. The results suggest that CI performance could be improved by adjustment of the frequency allocation, based on a measure of insertion angle and/or electrode discrimination ability.
Acoustics of fish shelters: Background noise and signal-to-noise ratio
Authors: Lugli Marco
Published: December 2014

Fish shelters (flat stones, shells, artificial covers, etc., with a hollow beneath) increase the sound pressure levels of low frequency sounds (<150 Hz) outside the nest cavity, see Lugli [(2012). J. Acoust. Soc. Am. 132, 3512–3524]. Since some calling males only produce sound when a female is inside the shelter, this study examines the effect of sound amplification by the shelter on signal-to-noise ratio (SNR) in the nest. Background noise amplification by the shelter was examined under both laboratory (stones and shells) and field (stones) conditions, and the SNR of tones inside the nest cavity was measured by performing acoustic tests on stones in the stream. Stone and shell shelters amplify the background noise pressure levels inside the cavity with comparable gains and at similar frequencies of an active sound source. Inside the cavity of stream stones, the mean SNR of tones increased significantly below 125 Hz and peaked at 65 Hz (+10 dB). Implications for fish acoustic communication inside nest enclosures are discussed.
Effects of masker type, sentence context, and listener age on speech recognition performance in 1-back listening tasks
Authors: Schurman Jaclyn , Brungart Douglas , Gordon-Salant Sandra
Published: December 2014

Studies have shown that older listeners with normal hearing have greater difficulty understanding speech in noisy environments than younger listeners even during simple assessments where listeners respond to auditory stimuli immediately after presentation. Older listeners may have increased difficulty understanding speech in challenging listening situations that require the recall of prior sentences during the presentation of new auditory stimuli. This study compared the performance of older and younger normal-hearing listeners in 0-back trials, which required listeners to respond to the most recent sentence, and 1-back trials, which required the recall of the sentence preceding the most recent. Speech stimuli were high-context and anomalous sentences with four types of maskers. The results show that older listeners have greater difficulty in the 1-back task than younger listeners with all masker types, even when SNR was adjusted to produce 80% correct performance in the 0-back task for both groups. The differences between the groups in the 1-back task may be explained by differences in working memory for the noise and spatially separated speech maskers but not in the conditions with co-located speech maskers, suggesting that older listeners have increased difficulty in memory-intensive speech perception tasks involving high levels of informational masking.
Modeling the effects of a posterior glottal opening on vocal fold dynamics with implications for vocal hyperfunction
Authors: Zañartu Matías , Galindo Gabriel E. , Erath Byron D. , Peterson Sean D. , Wodicka George R. , Hillman Robert E.
Published: December 2014

Despite the frequent observation of a persistent opening in the posterior cartilaginous glottis in normal and pathological phonation, its influence on the self-sustained oscillations of the vocal folds is not well understood. The effects of a posterior gap on the vocal fold tissue dynamics and resulting acoustics were numerically investigated using a specially designed flow solver and a reduced-order model of human phonation. The inclusion of posterior gap areas of 0.03–0.1 cm2 reduced the energy transfer from the fluid to the vocal folds by more than 42%–80% and the radiated sound pressure level by 6–14 dB, respectively. The model was used to simulate vocal hyperfucntion, i.e., patterns of vocal misuse/abuse associated with many of the most common voice disorders. In this first approximation, vocal hyperfunction was modeled by introducing a compensatory increase in lung air pressure to regain the vocal loudness level that was produced prior to introducing a large glottal gap. This resulted in a significant increase in maximum flow declination rate and amplitude of unsteady flow, thereby mimicking clinical studies. The amplitude of unsteady flow was found to be linearly correlated with collision forces, thus being an indicative measure of vocal hyperfunction.
Physiological Characteristics of Well-Trained Junior Sprint Kayak Athletes
Authors: Borges Thiago Oliveira , Dascombe Ben , Bullock Nicola , Coutts Aaron J.
Published: December 2014

This study aimed to profile the physiological characteristics of junior sprint kayak athletes (n = 21, VO2max 4.1 ± 0.7 L/min, training experience 2.7 ± 1.2 y) and to establish the relationship between physiological variables (VO2max, VO2 kinetics, muscle-oxygen kinetics, paddling efficiency) and sprint kayak performance. VO2max, power at VO2max, power:weight ratio, paddling efficiency, VO2 at lactate threshold, and whole-body and muscle oxygen kinetics were determined on a kayak ergometer in the laboratory. Separately, on-water time trials (TT) were completed over 200 m and 1000 m. Large to nearly perfect (−.5 to −.9) inverse relationships were found between the physiological variables and on-water TT performance across both distances. Paddling efficiency and lactate threshold shared moderate to very large correlations (−.4 to −.7) with 200- and 1000-m performance. In addition, trivial to large correlations (−.11 to −.5) were observed between muscle-oxygenation parameters, muscle and whole-body oxygen kinetics, and performance. Multiple regression showed that 88% of the unadjusted variance for the 200-m TT performance was explained by VO2max, peripheral muscle deoxygenation, and maximal aerobic power (P < .001), whereas 85% of the unadjusted variance in 1000-m TT performance was explained by VO2max and deoxyhemoglobin (P < .001). The current findings show that well-trained junior sprint kayak athletes possess a high level of relative aerobic fitness and highlight the importance of the peripheral muscle metabolism for sprint kayak performance, particularly in 200-m races, where finalists and nonfinalists are separated by very small margins. Such data highlight the relative aerobic-fitness variables that can be used as benchmarks for talent-identification programs or monitoring longitudinal athlete development. However, such approaches need further investigation.
Relationships Between Rating-of-Perceived-Exertion- and Heart- Rate-Derived Internal Training Load in Professional Soccer Players: A Comparison of On-Field Integrated Training Sessions
Authors: Campos-Vazquez Miguel Angel , Mendez-Villanueva Alberto , Gonzalez-Jurado Jose Antonio , León-Prados Juan Antonio , Santalla Alfredo , Suarez-Arrones Luis
Published: December 2014

Purpose:

To describe the internal training load (ITL) of common training sessions performed during a typical week and to determine the relationships between different indicators of ITL commonly employed in professional football (soccer).

Methods:

Session-rating-of-perceived-exertion TL (sRPE-TL) and heart-rate- (HR) derived measurements of ITL as Edwards TL and Stagno training impulses (TRIMPMOD) were used in 9 players during 3 periods of the season. The relationships between them were analyzed in different training sessions during a typical week: skill drills/circuit training + small-sided games (SCT+SSGs), ball-possession games + technical-tactical exercises (BPG+TTE), tactical training (TT), and prematch activation (PMa).

Results:

HR values obtained during SCT+SSGs and BPG+TTE were substantially greater than those in the other 2 sessions, all the ITL markers and session duration were substantially greater in SCT+SSGs than in any other session, and all ITL measures in BPG+TTE were substantially greater than in TT and PMa sessions. Large relationships were found between HR >80% HRmax and HR >90% HRmax vs sRPE-TL during BPG+TTE and TT sessions (r = .61−.68). Very large relationships were found between Edwards TL and sRPE-TL and between TRIMPMOD and sRPE-TL in sessions with BPG+TTE and TT (r = .73−.87). Correlations between the different HR-based methods were always extremely large (r = .92−.98), and unclear correlations were observed for other relationships between variables.

Conclusion:

sRPE-TL provided variable-magnitude within-individual correlations with HR-derived measures of training intensity and load during different types of training sessions typically performed during a week in professional soccer. Caution should be applied when using RPE- or HR-derived measures of exercise intensity/load in soccer training interchangeably.
Hip-Abduction Torque and Muscle Activation in People With Low Back Pain
Authors: Sutherlin Mark A. , Hart Joseph M.
Published: December 2014

Context:

Individuals with a history of low back pain (LBP) may present with decreased hip-abduction strength and increased trunk or gluteus maximus (GMax) fatigability. However, the effect of hip-abduction exercise on hip-muscle function has not been previously reported.

Objective:

To compare hip-abduction torque and muscle activation of the hip, thigh, and trunk between individuals with and without a history of LBP during repeated bouts of side-lying hip-abduction exercise.

Design:

Repeated measures.

Setting:

Clinical laboratory.

Participants:

12 individuals with a history of LBP and 12 controls.

Intervention:

Repeated 30-s hip-abduction contractions.

Main Outcome Measures:

Hip-abduction torque, normalized root-mean-squared (RMS) muscle activation, percent RMS muscle activation, and forward general linear regression.

Results:

Hip-abduction torque reduced in all participants as a result of exercise (1.57 ± 0.36 Nm/kg, 1.12 ± 0.36 Nm/kg; P < .001), but there were no group differences (F = 0.129, P = .723) or group-by-time interactions (F = 1.098, P = .358). All participants had increased GMax activation during the first bout of exercise (0.96 ± 1.00, 1.18 ± 1.03; P = .038). Individuals with a history of LBP had significantly greater GMax activation at multiple points during repeated exercise (P < .05) and a significantly lower percent of muscle activation for the GMax (P = .050) at the start of the third bout of exercise and for the biceps femoris (P = .039) at the end of exercise. The gluteal muscles best predicted hip-abduction torque in controls, while no consistent muscles were identified for individuals with a history of LBP.

Conclusions:

Hip-abduction torque decreased in all individuals after hip-abduction exercise, although individuals with a history of LBP had increased GMax activation during exercise. Gluteal muscle activity explained hip-abduction torque in healthy individuals but not in those with a history of LBP. Alterations in hip-muscle function may exist in individuals with a history of LBP.
Mulligan Concept Use and Clinical Profile From the Perspective of American Certified Mulligan Practitioners
Authors: May James , Krzyzanowicz Ryan , Nasypany Alan , Baker Russell , Seegmiller Jeffrey
Published: December 2014

Context:

Although randomized controlled trials indicate that the Mulligan Concept (MC) of mobilization with movement can improve pain-free grip strength and pressure pain threshold in patients with lateral epicondylalgia of the elbow, improve ankle dorsiflexion in patients with subacute ankle sprains, and decrease the signs and symptoms of patients with cervicogenic headache, little is known about the clinical application, use, and profile of certified Mulligan practitioners (CMPs) in America.

Objective:

To better understand the use and value of applying the MC philosophy in clinical-care environments from the perspective of American CMPs while establishing a clinical profile of a CMP.

Design:

Quantitative descriptive design. Setting: Online survey instrument.

Participants:

American CMPs.

Data Collection and Analysis:

Online survey instrument.

Results:

CMPs use the MC to treat a broad spectrum of spinal and peripheral clinical pathologies in primarily outpatient clinics with an active and athletic population. American CMPs also find value in the MC.

Conclusions:

American CMPs continue to use and find value in the MC intervention strategy to treat a broad spectrum of spinal and peripheral conditions in their clinical practices.
Neutrophils scan for activated platelets to initiate inflammation
Authors: Sreeramkumar Vinatha , Adrover José M. , Ballesteros Ivan , Cuartero Maria Isabel , Rossaint Jan , Bilbao Izaskun , Nácher Maria , Pitaval Christophe , Radovanovic Irena , Fukui Yoshinori , McEver Rodger P. , Filippi Marie-Dominique , Lizasoain Ignacio , Ruiz-Cabello Jesús , Zarbock Alexander , Moro María A. , Hidalgo Andrés
Published: December 2014

Immune and inflammatory responses require leukocytes to migrate within and through the vasculature, a process that is facilitated by their capacity to switch to a polarized morphology with an asymmetric distribution of receptors. We report that neutrophil polarization within activated venules served to organize a protruding domain that engaged activated platelets present in the bloodstream. The selectin ligand PSGL-1 transduced signals emanating from these interactions, resulting in the redistribution of receptors that drive neutrophil migration. Consequently, neutrophils unable to polarize or to transduce signals through PSGL-1 displayed aberrant crawling, and blockade of this domain protected mice against thromboinflammatory injury. These results reveal that recruited neutrophils scan for activated platelets, and they suggest that the neutrophils’ bipolarity allows the integration of signals present at both the endothelium and the circulation before inflammation proceeds.
Summer jobs reduce violence among disadvantaged youth
Authors: Heller Sara B.
Published: December 2014

Every day, acts of violence injure more than 6000 people in the United States. Despite decades of social science arguing that joblessness among disadvantaged youth is a key cause of violent offending, programs to remedy youth unemployment do not consistently reduce delinquency. This study tests whether summer jobs, which shift focus from remediation to prevention, can reduce crime. In a randomized controlled trial among 1634 disadvantaged high school youth in Chicago, assignment to a summer jobs program decreases violence by 43% over 16 months (3.95 fewer violent-crime arrests per 100 youth). The decline occurs largely after the 8-week intervention ends. The results suggest the promise of using low-cost, well-targeted programs to generate meaningful behavioral change, even with a problem as complex as youth violence.
Ultrafast generation of pseudo-magnetic field for valley excitons in WSe
2
monolayers
Authors: Kim Jonghwan , Hong Xiaoping , Jin Chenhao , Shi Su-Fei , Chang Chih-Yuan S. , Chiu Ming-Hui , Li Lain-Jong , Wang Feng
Published: December 2014

The valley pseudospin is a degree of freedom that emerges in atomically thin two-dimensional transition metal dichalcogenides (MX
2
). The capability to manipulate it, in analogy to the control of spin in spintronics, can open up exciting opportunities. Here, we demonstrate that an ultrafast and ultrahigh valley pseudo-magnetic field can be generated by using circularly polarized femtosecond pulses to selectively control the valley degree of freedom in monolayer MX
2.
Using ultrafast pump-probe spectroscopy, we observed a pure and valley-selective optical Stark effect in WSe
2
monolayers from the nonresonant pump, resulting in an energy splitting of more than 10 milli–electron volts between the K and K′ valley exciton transitions. Our study opens up the possibility to coherently manipulate the valley polarization for quantum information applications.
Chromatin decondensation is sufficient to alter nuclear organization in embryonic stem cells
Authors: Therizols Pierre , Illingworth Robert S. , Courilleau Celine , Boyle Shelagh , Wood Andrew J. , Bickmore Wendy A.
Published: December 2014

During differentiation, thousands of genes are repositioned toward or away from the nuclear envelope. These movements correlate with changes in transcription and replication timing. Using synthetic (TALE) transcription factors, we found that transcriptional activation of endogenous genes by a viral trans-activator is sufficient to induce gene repositioning toward the nuclear interior in embryonic stem cells. However, gene relocation was also induced by recruitment of an acidic peptide that decondenses chromatin without affecting transcription, indicating that nuclear reorganization is driven by chromatin remodeling rather than transcription. We identified an epigenetic inheritance of chromatin decondensation that maintained central nuclear positioning through mitosis even after the TALE transcription factor was lost. Our results also demonstrate that transcriptional activation, but not chromatin decondensation, is sufficient to change replication timing.
Unknown significance
Authors: Couzin-Frankel Jennifer
Published: December 2014

Years of writing about genetic testing did not prepare me for my own foray into this rapidly changing world.
Sleeping dogs of the genome
Authors: Gorbunova Vera , Boeke Jef D. , Helfand Stephen L. , Sedivy John M.
Published: December 2014

Retrotransposable elements may be agents of somatic diversity, disease, and aging
Serogroup-Specific Bacterial Engineered Glycoproteins as Novel Antigenic Targets for Diagnosis of Shiga Toxin-Producing-Escherichia coli-Associated Hemolytic-Uremic Syndrome
Authors: Melli Luciano J. , Ciocchini Andrés E. , Caillava Ana J. , Vozza Nicolás , Chinen Isabel , Rivas Marta , Feldman Mario F. , Ugalde Juan E. , Comerci Diego J.
Published: December 2014

Human infection with Shiga toxin-producing
Escherichia coli
(STEC) is a major cause of postdiarrheal hemolytic-uremic syndrome (HUS), a life-threatening condition characterized by hemolytic anemia, thrombocytopenia, and acute renal failure.
E. coli
O157:H7 is the dominant STEC serotype associated with HUS worldwide, although non-O157 STEC serogroups can cause a similar disease. The detection of anti-O157
E. coli
lipopolysaccharide (LPS) antibodies in combination with stool culture and detection of free fecal Shiga toxin considerably improves the diagnosis of STEC infections. In the present study, we exploited a bacterial glycoengineering technology to develop recombinant glycoproteins consisting of the O157, O145, or O121 polysaccharide attached to a carrier protein as serogroup-specific antigens for the serological diagnosis of STEC-associated HUS. Our results demonstrate that using these antigens in indirect ELISAs (glyco-iELISAs), it is possible to clearly discriminate between STEC O157-, O145-, and O121-infected patients and healthy children, as well as to confirm the diagnosis in HUS patients for whom the classical diagnostic procedures failed. Interestingly, a specific IgM response was detected in almost all the analyzed samples, indicating that it is possible to detect the infection in the early stages of the disease. Additionally, in all the culture-positive HUS patients, the serotype identified by glyco-iELISAs was in accordance with the serotype of the isolated strain, indicating that these antigens are valuable not only for diagnosing HUS caused by the O157, O145, and O121 serogroups but also for serotyping and guiding the subsequent steps to confirm diagnosis.
Pseudorabies Virus Triggers Glycoprotein gE-Mediated ERK1/2 Activation and ERK1/2-Dependent Migratory Behavior in T Cells
Authors: Setas Pontes Maria , Devriendt Bert , Favoreel Herman W.
Published: December 2014

The interaction between viruses and immune cells of the host may lead to modulation of intracellular signaling pathways and to subsequent changes in cellular behavior that are of benefit for either virus or host. ERK1/2 (extracellular signal regulated kinase 1/2) signaling represents one of the key cellular signaling axes. Here, using wild-type and gE null virus, recombinant gE, and gE-transfected cells, we show that the gE glycoprotein of the porcine
Varicellovirus
pseudorabies virus (PRV) triggers ERK1/2 phosphorylation in Jurkat T cells and primary porcine T lymphocytes. PRV-induced ERK1/2 signaling resulted in homotypic T cell aggregation and increased motility of T lymphocytes. Our study reveals a new function of the gE glycoprotein of PRV and suggests that PRV, through activation of ERK1/2 signaling, has a substantial impact on T cell behavior.

IMPORTANCE
Herpesviruses are known to be highly successful in evading the immune system of their hosts, subverting signaling pathways of the host to their own advantage. The ERK1/2 signaling pathway, being involved in many cellular processes, represents a particularly attractive target for viral manipulation. Glycoprotein E (gE) is an important virulence factor of alphaherpesviruses, involved in viral spread. In this study, we show that gE has the previously uncharacterized ability to trigger ERK1/2 phosphorylation in T lymphocytes. We also show that virus-induced ERK1/2 signaling leads to increased migratory behavior of T cells and that migratory T cells can spread the infection to susceptible cells. In conclusion, our results point to a novel function for gE and suggest that virus-induced ERK1/2 activation may trigger PRV-carrying T lymphocytes to migrate and infect other cells susceptible to PRV replication.
GB Virus C Coinfections in West African Ebola Patients
Authors: Lauck Michael , Bailey Adam L. , Andersen Kristian G. , Goldberg Tony L. , Sabeti Pardis C. , O'Connor David H.
Published: December 2014

In 49 patients with known Ebola virus disease outcomes during the ongoing outbreak in Sierra Leone, 13 were coinfected with the immunomodulatory pegivirus GB virus C (GBV-C). Fifty-three percent of these GBV-C
+
patients survived; in contrast, only 22% of GBV-C
−
patients survived. Both survival and GBV-C status were associated with age, with older patients having lower survival rates and intermediate-age patients (21 to 45 years) having the highest rate of GBV-C infection. Understanding the separate and combined effects of GBV-C and age on Ebola virus survival may lead to new treatment and prevention strategies, perhaps through age-related pathways of immune activation.
Mutations across Murine Hepatitis Virus nsp4 Alter Virus Fitness and Membrane Modifications
Authors: Beachboard Dia C. , Anderson-Daniels Jordan M. , Denison Mark R.
Published: December 2014

A common feature of infection by positive-sense RNA virus is the modification of host cell cytoplasmic membranes that serve as sites of viral RNA synthesis. Coronaviruses induce double-membrane vesicles (DMVs), but the role of DMVs in replication and virus fitness remains unclear. Coronaviruses encode 16 nonstructural proteins (nsps), three of which, nsp3, nsp4, and nsp6, are necessary and sufficient for DMV formation. It has been shown previously that mutations in murine hepatitis virus (MHV) nsp4 loop 1 that alter nsp4 glycosylation are associated with disrupted DMV formation and result in changes in virus replication and RNA synthesis. However, it is not known whether DMV morphology or another function of nsp4 glycosylation is responsible for effects on virus replication. In this study, we tested whether mutations across nsp4, both alone and in combination with mutations that abolish nsp4 glycosylation, affected DMV formation, replication, and fitness. Residues in nsp4 distinct from glycosylation sites, particularly in the endoplasmic reticulum (ER) luminal loop 1, independently disrupted both the number and morphology of DMVs and exacerbated DMV changes associated with loss of glycosylation. Mutations that altered DMV morphology but not glycosylation did not affect virus fitness while viruses lacking nsp4 glycosylation exhibited a loss in fitness. The results support the hypothesis that DMV morphology and numbers are not key determinants of virus fitness. The results also suggest that nsp4 glycosylation serves roles in replication in addition to the organization and stability of MHV-induced double-membrane vesicles.

IMPORTANCE
All positive-sense RNA viruses modify host cytoplasmic membranes for viral replication complex formation. Thus, defining the mechanisms of virus-induced membrane modifications is essential for both understanding virus replication and development of novel approaches to virus inhibition. Coronavirus-induced membrane changes include double-membrane vesicles (DMVs) and convoluted membranes. Three viral nonstructural proteins (nsps), nsp3, nsp4, and nsp6, are known to be required for DMV formation. It is unknown how these proteins induce membrane modification or which regions of the proteins are involved in DMV formation and stability. In this study, we show that mutations across nsp4 delay virus replication and disrupt DMV formation and that loss of nsp4 glycosylation is associated with a substantial fitness cost. These results support a critical role for nsp4 in DMV formation and virus fitness.
Induction of an Embryonic Mouse Innate Immune Response following Inoculation In Utero with Minute Virus of Mice
Authors: Rostovsky Irina , Davis Claytus
Published: December 2014

We used an embryonic-infection model system to show that MVMp, the prototypic minute virus of mice (MVM) serotype and a member of the genusProtoparvovirus, triggers a comprehensive innate immune response in the developing mouse embryo. Direct inoculation of the midtrimester embryoin uterowith MVMp results in a widespread, productive infection. During a 96-h infection course, embryonic beta interferon (IFN-β) and IFN-γ transcription were induced 90- and 60-fold, respectively. IFN-β levels correlated with the embryo viral burden, while IFN-γ levels first increased and then decreased. Production of proinflammatory cytokines, interleukin 1β (IL-1β) and tumor necrosis factor alpha (TNF-α), also increased, but by smaller amounts, approximately 7-fold each. We observed increased levels of downstream antiviral effector molecules, PKR and phosphorylated STAT2. Finally, we showed that there is an immune cell response to the virus infection. Infected tissues in the embryo exhibited an increased density of mature leukocytes compared to the same tissues in uninfected embryos. The responses we observed were almost completely restricted to the infected embryos. Uninfected littermates routinely exhibited small increases in innate immune components that rarely reached statistical significance compared to negative controls. Similarly, the placentae of infected embryos did not show any significant increase in transcription of innate immune cytokines. Since the placenta has both embryonic and maternal components, we suggest there is minimal involvement of the dam in the response to infection.

IMPORTANCEInteraction between the small single-stranded vertebrate DNA viruses, the protoparvoviruses, and the host innate immune system has been unclear. The issue is important practically given the potential use of these viruses as oncotherapeutic agents. The data reported here stand in contrast to studies of innate immune response during protoparvovirus infection of adult hosts, which invariably reported no or minimal and sporadic induction of an interferon response during infection. We conclude that under conditions of robust and productive MVM infection, a normal murine host is able to mount a significant and broad innate immune response.
Deletion of the ORF9p Acidic Cluster Impairs the Nuclear Egress of Varicella-Zoster Virus Capsids
Authors: Riva Laura , Thiry Marc , Lebrun Marielle , L'homme Laurent , Piette Jacques , Sadzot-Delvaux Catherine
Published: December 2014

The protein encoded by ORF9 is essential for varicella-zoster virus (VZV) replication. Previous studies documented its presence in the
trans
-Golgi network and its involvement in secondary envelopment. In this work, we deleted the ORF9p acidic cluster, destroying its interaction with ORF47p, and this resulted in a nuclear accumulation of both proteins. This phenotype results in an accumulation of primary enveloped capsids in the perinuclear space, reflecting a capsid de-envelopment defect.
From Fock’s transformation to de Sitter space
Authors: Foughali T. , Bouda A.
Published: December 2014

As with Deformed Special Relativity, we showed recently that the Fock coordinate transformation can be derived from a new deformed Poisson brackets. This approach allowed us to establish the corresponding momentum transformation that keeps invariant the four-dimensional contraction pμxμ. From the resulting deformed algebra, we construct the corresponding first Casimir. After first quantization, we show by using the Klein–Gordon equation that the space-time of the Fock transformation is the de Sitter one. As we will see, the invariant length representing the universe radius in the space-time of Fock’s transformation is exactly the radius of the embedded hypersurface representing the de Sitter space-time.
Some peculiarities of formation of 4He nuclei in 16Op collisions at 3.25A GeV/c
Authors: Olimov Kosim , Lutpullaev Sagdulla L. , Olimov Khusniddin K. , Olimov Alisher K. , Petrov Vladimir I. , Glagolev Viktor V. , Yuldashev B. S.
Published: December 2014

The new experimental data on dependences of the mean multiplicities and kinematical characteristics of 4 He nuclei, formed in 16 O p collisions at 3.25A GeV/c, on degree of excitation of the fragmenting nucleus are presented. It is shown that the initial (α cluster) structure of oxygen nucleus is retained at small excitation levels. It is established that the kinematical characteristics of 1 H , 2 H , 3 H and 3 He fragments do not depend on availability or absence of α particles in a collision event, which indicates the independence of mechanisms of formation of such fragments and 4 He nuclei.