bluuebunny/crossref_metadata_2025 huggingface dataset:
RAD‐seq phylogenomics recovers a well‐resolved phylogeny of a rapid radiation of mutualistic and antagonistic yucca moths
Authors: DARWELL CLIVE T. , RIVERS DAVID M. , ALTHOFF DAVID M.
Published: May 2016

The interaction between yucca plants and yucca moths has been one of the focal model systems investigated in the study of pollination mutualism and coevolution, especially in terms of understanding the prevention of overexploitation by mutualist partners. Yuccas have the ability to assess the number of eggs placed by pollinators into their ovaries, and can preferentially abort those flowers that would have many moth larvae consuming yucca seeds. Previous phylogenetic research identified a rapid radiation of moth species that corresponded with shifts in the interaction with their host plants. These shifts led to the evolution of moth species that circumvent the egg detection method used by yuccas to limit seed damage. In particular, some pollinator species deposit their eggs so that they are undetectable by the plants, whereas other species are ‘cheaters’ that have lost the ability to pollinate, yet deposit eggs into developing fruit rather than flowers. The evolution of these new species happened so quickly that the phylogeny of the moths has remained unresolved despite repeated attempts with standard Sanger sequencing of mtDNA loci and AFLP marker generation. Here, we use extensive analyses of RAD‐seq data to determine the phylogenetic relationships among yucca moth species. The results provide a robust phylogenetic framework that identifies the evolutionary relationships among shifts in egg‐laying strategies, as well as determining the closest pollinating relatives to the cheater species. Based on the obtained phylogeny, a shift in egg‐laying strategy that avoided the overexploitation regulatory mechanism used by yucca plants was a precursor for the evolution of two species with cheating behaviour.
Cover Image, Volume 14, Issue 2
Authors: Finotello R. , Ressel L. , Arvigo M. , Baroni G. , Marchetti V. , Romanelli G. , Burrow R. , Mignacca D. , Blackwood L.
Published: May 2016

The cover image, by Riccardo Finotello et al., is based on the Original Article Canine pancreatic islet cell tumours secreting insulin‐like growth factor type 2 (IGF‐II): a rare entity, DOI: 10.1111/vco.12085.

image
Quality of life assessment in dogs and cats receiving chemotherapy – a review of current methods
Authors: Vøls Kåre K. , Heden Martin A. , Kristensen Annemarie T. , Sandøe Peter
Published: May 2016

This study aimed to review currently reported methods of assessing the effects of chemotherapy on the quality of life (QoL) of canine and feline patients and to explore novel ways to assessQoLin such patients in the light of the experience to date in human pediatric oncology. A qualitative comparative analysis of published papers on the effects of chemotherapy onQoLin dogs and cats were conducted. This was supplemented with a comparison of the parameters and domains used in veterinaryQoL‐assessments with those used in the Pediatric Quality of Life Inventory (PedsQL™) questionnaire designed to assessQoLin toddlers. Each of the identified publications includingQoL‐assessment in dogs and cats receiving chemotherapy applied a different method ofQoL‐assessment. In addition, the veterinaryQoL‐assessments were mainly focused on physical clinical parameters, whereas the emotional (6/11), social (4/11) and role (4/11) domains were less represented.QoL‐assessment of cats and dogs receiving chemotherapy is in its infancy. The most commonly reported method to assessQoLwas questionnaire based and mostly included physical and clinical parameters. Standardizing and including a complete range of potentially relevant parameters in futureQoLassessments may benefit owner decision making.
Study on the Stress-Stiffening Effect and Modal Synthesis Methods for the Dynamics of a Spatial Curved Beam
Authors: Zhang Jianshu , Rui Xiaoting , Li Bo , Chen Gangli
Published: May 2016

In this paper, based on the nonlinear strain–deformation relationship, the dynamics equation of a spatial curved beam undergoing large displacement and small deformation is deduced using the finite-element method of floating frame of reference (FEMFFR) and Hamiltonian variation principle. The stress-stiffening effect, which is also called geometric stiffening effect, is accounted for in the dynamics equation, which makes it possible for the dynamics simulation of the spatial curved beam with high rotational speed. A numerical example is carried out by using the deduced dynamics equation to analyze the stress-stiffening effect of the curved beam and then verified by abaqus software. Then, the modal synthesis methods, which result in much fewer numbers of coordinates, are employed to improve the computational efficiency.
Simulating Size and Volume Fraction-Dependent Strength and Ductility of Nanotwinned Composite Copper
Authors: Zhu Linli , Guo Xiang , Ruan Haihui
Published: May 2016

This work presents a micromechanical model to investigate mechanical properties of nanotwinned dual-phase copper, consisting of the coarse grained phase and the nanotwinned phase. Both strengthening mechanisms of nanotwinning and the contributions of nanovoids/microcracks have been taken into account in simulations. With the aid of modified mean-field approach, the stress–strain relationship is derived by combining the constitutive relations of the coarse grained phase and the nanotwinned phase. Numerical results show that the proposed model enables us to describe the mechanical properties of the nanotwinned composite copper, including both yield strength and ductility. The calculations based on the proposed model agree well with the results from finite element method (FEM). The predicted yield strength and ductility are sensitive to the twin spacing, grain size, as well as the volume fractions of phases in this composite copper. These results will benefit the optimization of both strength and ductility by controlling constituent fractions and the size of the microstructures in metallic materials.
Basic Analysis of the Incremental Profile Forming Process
Authors: Grzancic Goran , Becker Christoph , Khalifa Nooman Ben
Published: May 2016

Increasing demands in profile manufacturing leads to a constant increase of the geometric complexity of the profile. Nowadays, lightweight design and load adaption are of huge importance and a need for new profile manufacturing technologies exists. In order to cope with this development, a new tube profile forming method was invented, the incremental profile forming (IPF). IPF allows the flexible manufacturing of profiles with varying cross section geometries along the longitudinal profile axis and offers therefore a high potential for the manufacturing of lightweight design parts. Due to the high degree of innovation, research work regarding the process fundamentals as well as the process limits is necessary. For this reason, the results of the first basic experimental and numerical investigations are presented. While in the experiments, the potential of the process is shown in feasibility studies, first analyses of the forming process, and the influence of different process parameters on the process were carried out in numerical investigations. In particular, it turned out that the tool infeed and tube dimensions have significant influence on the forming force, whereas the tool radius has a minor influence.
Application of Gotoh's Orthotropic Yield Function for Modeling Advanced High-Strength Steel Sheets
Authors: Tong Wei
Published: May 2016

An accurate description of the directional dependence of uniaxial tensile yielding and plastic flow in advanced high-strength steel sheets may require either a nonassociated plasticity model with separate quadratic yield function and flow potential or an associated plasticity model with nonquadratic yield function. In this paper, Gotoh's fourth-order homogeneous polynomial yield function is applied to model two advanced high-strength steel sheets in an associated plasticity model. Both the parameter selection for calibrating Gotoh's yield function and its positivity and convexity verification are given in some detail. Similarities and differences between the associated plasticity model presented here and the nonassociated one appeared in the literature are discussed in terms of the directional dependence of yield stresses and plastic strain ratios under uniaxial tension and yield stresses under biaxial tension loading.
Predicting Microstructure From Thermal History During Additive Manufacturing for Ti-6Al-4V
Authors: Irwin Jeff , Reutzel Edward W. , Michaleris Pan , Keist Jay , Nassar Abdalla R.
Published: May 2016

Due to the repeated thermal cycling that occurs with the processing of each subsequent layer, the microstructure of additively manufactured parts undergoes complex changes throughout the deposition process. Understanding and modeling this evolution poses a greater challenge than for single-cycle heat treatments. Following the work of Kelly and Charles, a Ti-6Al-4V microstructural model has been developed which calculates the phase fractions, morphology, and alpha lath width given a measured or modeled thermal history. Dissolution of the alpha phase is modeled as 1D plate growth of the beta phase, while alpha growth is modeled by the technique of Johnson–Mehl–Avrami (JMA). The alpha phase is divided into colony and basketweave morphologies based on an intragranular nucleation temperature. Evolution of alpha lath width is calculated using an Arrhenius equation. Key parameters of the combined Kelly–Charles model developed here are optimized using the Nelder–Mead simplex algorithm. For the deposition of two L-shaped geometries with different processing parameters, the optimized model gives a mean error over 24 different locations of 37% relative to experimentally measured lath widths, compared to 106% for the original Kelly–Charles model.
Experimental and Numerical Study on the Reduction of Residual Stress in the Fillet Weld by Overlay Welding and Cutting Method
Authors: Luo Yun , Jiang Wenchun , Zhang Qian , Wan Yu , Zhang W. Y. , Wang Y. J.
Published: May 2016

Fillet weld joint is widely used in engineering structures, but a lot of failures have been generated in the fillet joint affected greatly by weld residual stress, and it is very important to decrease the residual stress. Therefore, this paper proposes a new method using overlay welding and cutting (OWC) to reduce the residual stress in the fillet weld. First, the overlay welding is applied on the root surface of fillet weld, and then the overlaid metal is removed again by cutting. In order to verify this method, a thermal-elasto-plastic analysis method, using finite-element analysis (FEA) techniques, is developed to evaluate the residual stress change during the process of OWC. The impact indention measurement is also used to measure the surface residual stress. The results of FEA were compared with experimental data to confirm the accuracy of the developed finite-element method (FEM). In order to provide a guideline for design, the dimension effects including overlay weld width and height on residual stress have been investigated. It finds that OWC can decrease 25–40% of the as-weld residual stress, and increasing the overlay width and height is helpful to decrease the residual stress, which provides a reference for the reduction of residual stress in the fillet weld.
Experimental Study on Failure Estimation Method for Circumferentially Cracked Pipes Subjected to Multi-Axial Loads
Authors: Li Yinsheng , Hasegawa Kunio , Miura Naoki , Hoshino Katsuaki
Published: May 2016

When a crack is detected in a piping line during in-service inspections, failure estimation method provided in ASME Boiler and Pressure Vessel Code Section XI (ASME Code Section XI) or JSME Rules on Fitness-for-Service for Nuclear Power Plants (JSME FFS Code) can be applied to evaluate the structural integrity of the cracked pipe. The failure estimation method in the current codes accounts for the bending moment and axial force due to pressure. The torsion moment is not considered. Recently, analytical investigation was carried out by the authors on the limit load of cracked pipes considering multi-axial loads including torsion. Two failure estimation methods for multi-axial loads including torsion moment with different ranges were proposed. In this study, to investigate the failure behavior of cracked pipes subjected to multi-axial loads including the torsion moment and to provide experimental support for the failure estimation methods, failure experiments were performed on 20 mm diameter stainless steel pipes with a circumferential surface crack or a through-wall crack under combined axial force, bending moment, and torsion moment. Based on the experimental results, the proposed failure estimation methods were confirmed to be applicable to cracked pipes subjected to multi-axial loads.
Study of Energy-Saving Potential of Electronically Controlled Turbocharger for Internal Combustion Engine Exhaust Gas Energy Recovery
Authors: Tang Qijun , Fu Jianqin , Liu Jingping , Zhou Feng , Duan Xiongbo
Published: May 2016

To promote the energy utilization efficiency of internal combustion engine, the approach of electronically controlled turbocharger (ECT) for IC engine exhaust gas energy recovery was investigated by the method of test coupling with numerical simulation. First, the tests for turbocharged gasoline engine and high-speed motor were conducted so as to provide experimental data for numerical simulation. Then, the simulation model of ECT engine was built and calibrated, and the working processes of ECT engine were simulated. The results show that the recovered exhaust gas energy by ECT increases with the decrease of by-pass valve opening due to the rising of exhaust gas mass flow rate, but the pumping loss also ascends; limited by the original engine turbocharger map, the engine working points are beyond turbine map when the by-pass valve opening increases to a certain degree. To further improve the energy recovery potential of ECT, a larger turbine was rematched, and the working processes of ECT engine under the whole operating conditions were resimulated. The results indicate that engine exhaust gas energy cannot be recovered by ECT in low-load and low-speed area due to the low exhaust gas pressure. In the effective working area, as the load and speed ascend, both the recovery efficiency of ECT and the utilization efficiency of exhaust gas energy increase, and their maximum values reach 8.4% and 18.4%, respectively. All those demonstrate that ECT can effectively recover engine exhaust gas energy.
Effect of Variable Properties and Radiation on Convective Heat Transfer Measurements at Engine Conditions
Authors: Greiner Nathan J. , Polanka Marc D. , Rutledge James L. , Shewhart Andrew T.
Published: May 2016

Convective heat transfer from a fluid to a surface is an approximately linear function of driving temperature if the properties within the boundary layer are approximately constant. However, in environments with large driving temperatures like those seen in the hot sections of gas turbine engines, significant property variations exist within the boundary layer. In addition, radiative heat transfer can be a significant contributor to the total heat transfer in a high-temperature environment such that it can not be neglected. As a result, heat transfer to the surface becomes a nonlinear function of driving temperature and the conventional linear heat flux assumption cannot be employed to characterize the convective heat transfer. The present study experimentally examines the nonlinearity of convective heat flux on a zero-pressure-gradient flat plate with large freestream to wall-temperature differences. In addition, the need to account for the radiative component of the overall heat transfer is highlighted. Finally, a method to account for the effects of both variable properties and radiation simultaneously is proposed and demonstrated. Overall, the proposed technique provides the means to quantify the independent contributions of radiative and variable property convective heat transfer to the total conductive heat transfer to or from a surface in a single experiment.
A simple expression for sound attenuation due to surface duct energy leakage in low-latitude oceans
Authors: Duan Rui , Yang Kunde , Ma Yuanliang , Chapman N. Ross
Published: May 2016

This paper presents an expression for the attenuation of sound energy in an ocean surface duct due to energy leakage outside the duct. Dominant parameters determining the attenuation are the sound frequency and the surface duct thickness. The attenuation is found to be exponentially dependent on a scaled frequency that combines the two parameters. Data from experiments in low-latitude oceans with three different surface duct thicknesses are used to verify the exponential expression derived for the attenuation.
Ultrasound and acoustic analysis of sibilant fricatives in preadolescents and adults
Authors: Zharkova Natalia
Published: May 2016

This study describes the production of sibilant fricatives /s/ and /∫/, comparing Scottish English speaking preadolescent children with adults. The materials were the sequences /əCa/ and /əCi/ produced by 15 adults and 15 children aged between 10 and 12 years old. Quantitative analyses were carried out on both spectral information and on ultrasound imaging data on tongue shape, taken from nine successive time points during the fricative. The two groups of speakers were very similar to each other in the articulatory and acoustic characteristics distinguishing the two fricatives. Age-related differences in the fricative centroid measure occurred at consonant-vowel boundaries, with lower values in the preadolescents. Within-speaker variability was mostly similar across age groups, with the exception of the fricative centroid for /∫/, which was significantly more variable in preadolescents than in adults. Throughout the consonant duration, both groups consistently differentiated between the two consonants in both the fricative centroid and in one measure of tongue shape.
Physical Predictors of Elite Skeleton Start Performance
Authors: Colyer Steffi L. , Stokes Keith A. , Bilzon James L.J. , Cardinale Marco , Salo Aki I.T.
Published: May 2016

Purpose:

An extensive battery of physical tests is typically employed to evaluate athletic status and/or development, often resulting in a multitude of output variables. The authors aimed to identify independent physical predictors of elite skeleton start performance to overcome the general problem of practitioners employing multiple tests with little knowledge of their predictive utility.

Methods:

Multiple 2-d testing sessions were undertaken by 13 high-level skeleton athletes across a 24-wk training season and consisted of flexibility, dry-land push-track, sprint, countermovement-jump, and leg-press tests. To reduce the large number of output variables to independent factors, principal-component analysis (PCA) was conducted. The variable most strongly correlated to each component was entered into a stepwise multiple-regression analysis, and K-fold validation assessed model stability.

Results:

PCA revealed 3 components underlying the physical variables: sprint ability, lower-limb power, and strength–power characteristics. Three variables that represented these components (unresisted 15-m sprint time, 0-kg jump height, and leg-press force at peak power, respectively) significantly contributed (P < .01) to the prediction (R2 = .86, 1.52% standard error of estimate) of start performance (15-m sled velocity). Finally, the K-fold validation revealed the model to be stable (predicted vs actual R2 = .77; 1.97% standard error of estimate).

Conclusions:

Only 3 physical-test scores were needed to obtain a valid and stable prediction of skeleton start ability. This method of isolating independent physical variables underlying performance could improve the validity and efficiency of athlete monitoring, potentially benefitting sport scientists, coaches, and athletes alike.
The Effects of Plyometric Training on Change-of-Direction Ability: A Meta-Analysis
Authors: Asadi Abbas , Arazi Hamid , Young Warren B. , de Villarreal Eduardo Sáez
Published: May 2016

Purpose:

To show a clear picture about the possible variables of enhancements of change-of-direction (COD) ability using longitudinal plyometric-training (PT) studies and determine specific factors that influence the training effects.

Methods:

A computerized search was performed, and 24 articles with a total of 46 effect sizes (ESs) in an experimental group and 25 ESs in a control group were reviewed to analyze the role of various factors on the impact of PT on COD performance.

Results:

The results showed that participants with good fitness levels obtained greater improvements in COD performance (P < .05), and basketball players gained more benefits of PT than other athletes. Also, men obtained COD results similar to those of women after PT. In relation to the variables of PT design, it appears that 7 wk (with 2 sessions/wk) using moderate intensity and 100 jumps per training session with a 72-h rest interval tends to improve COD ability. Performing PT with a combination of different types of plyometric exercises such as drop jumps + vertical jumps + standing long jumps is better than 1 form of exercise.

Conclusion:

It is apparent that PT can be effective at improving COD ability. The loading parameters are essential for exercise professionals, coaches, and strength and conditioning professionals with regard to the most appropriate dose-response trends to optimize plyometric-induced COD-ability gains.
Single-Leg Power Output and Between-Limbs Imbalances in Team-Sport Players: Unilateral Versus Bilateral Combined Resistance Training
Authors: Gonzalo-Skok Oliver , Tous-Fajardo Julio , Suarez-Arrones Luis , Arjol-Serrano José Luis , Casajús José Antonio , Mendez-Villanueva Alberto
Published: May 2016

Purpose:

To compare the effects of unilateral and bilateral resistance training on single-leg power output, between-limbs imbalance (BLI), bilateral deficit (BLD), change of direction (COD), and linear sprinting and jumping performance in young elite basketball players.

Methods:

Twenty-two young (U-16–U-19) male basketball players were randomly assigned either to an exclusive unilateral (UNI) (n = 11) or a bilateral (BIL) (n = 11) resistance-training group during a 6-wk period. Both groups training consisted of 3 unilateral or bilateral 90° back-squat sets. A postdetermined number of repetitions was set until power output dropped to <10% of maximum power (MP) output. In addition, both groups performed 2 sets of 5 unilateral or bilateral drop jumps and 2 sets of 5 unilateral or bilateral countermovement jumps (CMJ). Pre- and posttraining, performance was assessed by an incremental bilateral and unilateral squat-load test, a multiple-COD test (V-cut test), a 15-m-sprint test (7.5 + 7.5 m) with one 180° COD performed with both right (180° RCOD) and left (180° LCOD) legs, a 25-m-sprint test (5- and 15-m split time), and a CMJ test.

Results:

Within-group analyses showed substantial improvements in 180° RCOD, bilateral and unilateral MP, 25-m-sprint test, and CMJ in both groups. Between-groups analyses showed substantially better results in 180° LCOD, MP with right and left legs, BLI, and BLD in UNI than in BIL.

Conclusions:

Both training programs substantially improved most of the physical-fitness tests, but only UNI reduced between-limbs asymmetry and achieved greater enhancements in actions that mostly required applying force unilaterally in basketball players.
Effect of ad Libitum Ice-Slurry and Cold-Fluid Ingestion on Cycling Time-Trial Performance in the Heat
Authors: Maunder Ed , Laursen Paul B. , Kilding Andrew E.
Published: May 2016

Purpose:

To compare the physiological and performance effects of ad libitum cold-fluid (CF) and ice-slurry (IS) ingestion on cycling time-trial (TT) performance in the heat.

Methods:

Seven well-trained male triathletes and cyclists completed 2 maximaleffort 40-km cycling TTs in hot (35°C) and humid (60% relative humidity) conditions. In randomized order, participants ingested CF or IS (initial temperatures 4°C and –1°C, respectively) ad libitum during exercise. At each 5-km interval, time elapsed, power output, rectal and skin temperature, heart rate, and perceptual measures were recorded. The actual CF and IS temperatures during the 40-km TT were determined post hoc.

Results:

Performance time (2.5% ± 2.6%, ES = 0.27) and mean power (–2.2% ± 3.2%, ES = –0.15) were likely worse in the IS trial. Differences in thermoregulatory and cardiovascular measures were largely unclear between trials, while feeling state was worse in the later stages of the IS trial (ES = –0.31 to –0.95). Fluid-ingestion volume was very likely lower in the IS trial (–29.7% ± 19.4%, ES = –0.97). The temperatures of CF and IS increased by 0.37°C/min and 0.02°C/min, respectively, over the mean TT duration.

Conclusions:

Ad libitum ingestion of CF resulted in improved 40-km cycling TT performance compared with IS. Participants chose greater fluid-ingestion rates in the CF trial than in the IS trial and had improved feeling state. These findings suggest that ad libitum CF ingestion is preferable to IS during cycling TTs under conditions of environmental heat stress.
Relationship Between Blood Flow and Performance Recovery: A Randomized, Placebo-Controlled Study
Authors: Borne Rachel , Hausswirth Christophe , Bieuzen François
Published: May 2016

Purpose:

To investigate the effect of different limb blood-flow levels on cycling-performance recovery, blood lactate concentration, and heart rate.

Methods:

Thirty-three high-intensity intermittent-trained athletes completed two 30-s Wingate anaerobic test sessions, 3 × 30-s (WAnT 1–3) and 1 × 30-s (WAnT 4), on a cycling ergometer. WAnT 1–3 and WAnT 4 were separated by a randomly assigned 24-min recovery intervention selected from among blood-flow restriction, passive rest, placebo stimulation, or neuromuscular electrical-stimulation-induced blood flow. Calf arterial inflow was measured by venous occlusion plethysmography at regular intervals throughout the recovery period. Performance was measured in terms of peak and mean power output during WAnT 1 and WAnT 4.

Results:

After the recovery interventions, a large (r = .68 [90% CL .42; .83]) and very large (r = .72 (90% CL .49; .86]) positive correlation were observed between the change in calf arterial inflow and the change in mean and peak power output, respectively. Calf arterial inflow was significantly higher during the neuromuscular-electrical-stimulation recovery intervention than with the blood-flow-restriction, passive-rest, and placebo-stimulation interventions (P < .001). This corresponds to the only intervention that allowed performance recovery (P > .05). No recovery effect was linked to heart rate or blood lactate concentration levels.

Conclusions:

For the first time, these data support the existence of a positive correlation between an increase in blood flow and performance recovery between bouts of high-intensity exercise. As a practical consideration, this effect can be obtained by using neuromuscular electrical stimulation-induced blood flow since this passive, simple strategy could be easily applied during short-term recovery.
Psychophysiological Responses to Repeated-Sprint Training in Normobaric Hypoxia and Normoxia
Authors: Brocherie Franck , Millet Grégoire P. , Girard Olivier
Published: May 2016

Purpose:

To compare psychophysiological responses to 6 repeated-sprint sessions in normobaric hypoxia (RSH) and normoxia (RSN) in team-sport athletes during a 2-wk “live high–train low” training camp.

Methods:

While residing under normobaric hypoxia (≥14 h/d, FiO2 14.5–14.2%), 23 lowland elite field hockey players performed, in addition to their usual training, 6 sessions (4 × 5 × 5-s maximal sprints, 25-s passive recovery, 5 min rest) under either RSH (FiO2 ~14.5%) or RSN (FiO2 21%). Sprint 1 and 5 times, physiological strain (heart rate [HR], arterial oxyhemoglobin saturation [SpO2]), and perceptual responses (overall peripheral discomfort, difficulty breathing, and lower-limb discomfort) were monitored.

Results:

During the 1st session, HR increased across sets (P < .001) independently of the conditions, while SpO2 was globally lower (P < .001) for RSH (averaged value: 91.9% ± 1.2%) vs RSN (96.9% ± 0.6%). Thereafter, SpO2 and HR remained similar across sessions for each condition. While 1st-sprint time remained similar, last-sprint time and fatigue index significantly decreased across sets (P < .01) and sessions (P < .05) but not between conditions. Ratings of overall perceived discomfort, difficulty breathing, and lower-limb discomfort were higher (P < .05) in RSH vs RSN at the 1st session. During subsequent sessions, values for overall perceived discomfort (time [P < .001] and condition [P < .05] effects), difficulty breathing (time effect; P < .001), and lower-limb discomfort (condition [P < .001] and interaction [P < .05] effects) decreased to a larger extent in RSH vs RSN.

Conclusion:

Despite higher hypoxia-induced physiological and perceptual strain during the 1st session, perceptual responses improved thereafter in RSH so as not to differ from RSN. This indicates an effective acclimation and tolerance to this innovative training.
PERK mediates the IRES-dependent translational activation of mRNAs encoding angiogenic growth factors after ischemic stress
Authors: Philippe Céline , Dubrac Alexandre , Quelen Cathy , Desquesnes Aurore , Van Den Berghe Loic , Ségura Christèle , Filleron Thomas , Pyronnet Stéphane , Prats Hervé , Brousset Pierre , Touriol Christian
Published: May 2016

PERK may promote blood vessel growth in oxygen-deprived muscles by ensuring the production of angiogenic factors.
Ferritin out iron with pups
Authors: VanHook Annalisa M.
Published: May 2016

A prokaryotic ubiquitin-like protein modulates the function of ferritin so that bacteria can grow under iron-limiting conditions.
Acetylated tau disrupts synaptic plasticity in Alzheimer’s disease
Authors: Ferrarelli Leslie K.
Published: May 2016

Reducing the acetylation of tau might restore cognitive function in Alzheimer’s patients.
A Silenced
vanA
Gene Cluster on a Transferable Plasmid Caused an Outbreak of Vancomycin-Variable Enterococci
Authors: Sivertsen Audun , Pedersen Torunn , Larssen Kjersti Wik , Bergh Kåre , Rønning Torunn Gresdal , Radtke Andreas , Hegstad Kristin
Published: May 2016

We report an outbreak of vancomycin-variable
vanA
+
enterococci (VVE) able to escape phenotypic detection by current guidelines and demonstrate the molecular mechanisms for
in vivo
switching into vancomycin resistance and horizontal spread of the
vanA
cluster. Forty-eight
vanA
+
Enterococcus faecium
isolates and one
Enterococcus faecalis
isolate were analyzed for clonality with pulsed-field gel electrophoresis (PFGE), and their
vanA
gene cluster compositions were assessed by PCR and whole-genome sequencing of six isolates. The susceptible VVE strains were cultivated in brain heart infusion broth containing vancomycin at 8 μg/ml for
in vitro
development of resistant VVE. The transcription profiles of susceptible VVE and their resistant revertants were assessed using quantitative reverse transcription-PCR. Plasmid content was analyzed with S1 nuclease PFGE and hybridizations. Conjugative transfer of
vanA
was assessed by filter mating. The only genetic difference between the
vanA
clusters of susceptible and resistant VVE was an IS
L3
-family element upstream of
vanHAX
, which silenced
vanHAX
gene transcription in susceptible VVE. Furthermore, the VVE had an insertion of IS
1542
between
orf2
and
vanR
that attenuated the expression of
vanHAX
. Growth of susceptible VVE occurred after 24 to 72 h of exposure to vancomycin due to excision of the IS
L3
-family element. The
vanA
gene cluster was located on a transferable broad-host-range plasmid also detected in outbreak isolates with different pulsotypes, including one
E. faecalis
isolate. Horizontally transferable silenced
vanA
able to escape detection and revert into resistance during vancomycin therapy represents a new challenge in the clinic. Genotypic testing of invasive vancomycin-susceptible enterococci by
vanA
-PCR is advised.
Involvement of Antibiotic Efflux Machinery in Glutathione-Mediated Decreased Ciprofloxacin Activity in Escherichia coli
Authors: Goswami Manish , Subramanian Mahesh , Kumar Ranjeet , Jass Jana , Jawali Narendra
Published: May 2016

We have analyzed the contribution of different efflux components to glutathione-mediated abrogation of ciprofloxacin's activity in
Escherichia coli
and the underlying potential mechanism(s) behind this phenomenon. The results indicated that glutathione increased the total active efflux, thereby partially contributing to glutathione-mediated neutralization of ciprofloxacin's antibacterial action in
E. coli
. However, the role of glutathione-mediated increased efflux becomes evident in the absence of a functional TolC-AcrAB efflux pump.
Dynamics of Mutations during Development of Resistance by Pseudomonas aeruginosa against Five Antibiotics
Authors: Feng Yanfang , Jonker Martijs J. , Moustakas Ioannis , Brul Stanley , ter Kuile Benno H.
Published: May 2016

Pseudomonas aeruginosa
is an opportunistic pathogen that causes considerable morbidity and mortality, specifically during intensive care. Antibiotic-resistant variants of this organism are more difficult to treat and cause substantial extra costs compared to susceptible strains. In the laboratory,
P. aeruginosa
rapidly developed resistance to five medically relevant antibiotics upon exposure to stepwise increasing concentrations. At several time points during the acquisition of resistance, samples were taken for whole-genome sequencing. The increase in the MIC of ciprofloxacin was linked to specific mutations in
gyrA
,
parC
, and
gyrB
, appearing sequentially. In the case of tobramycin, mutations in
fusA
,
HP02880
,
rplB
, and
capD
were induced. The MICs of the beta-lactam compounds meropenem and ceftazidime and the combination of piperacillin and tazobactam correlated linearly with beta-lactamase activity but not always with individual mutations. The genes that were mutated during the development of beta-lactam resistance differed for each antibiotic. A quantitative relationship between the frequency of mutations and the increase in resistance could not be established for any of the antibiotics. When the adapted strains are grown in the absence of the antibiotic, some mutations remained and others were reversed, but this reversal did not necessarily lower the MIC. The increased MIC came at the cost of moderately reduced cellular functions or a somewhat lower growth rate. In all cases except ciprofloxacin, the increase in resistance seems to be the result of complex interactions among several cellular systems rather than individual mutations.
Synergy between Colistin and the Signal Peptidase Inhibitor MD3 Is Dependent on the Mechanism of Colistin Resistance in Acinetobacter baumannii
Authors: Martínez-Guitián Marta , Vázquez-Ucha Juan C. , Odingo Joshua , Parish Tanya , Poza Margarita , Waite Richard D. , Bou German , Wareham David W. , Beceiro Alejandro
Published: May 2016

Synergy between colistin and the signal peptidase inhibitor MD3 was tested against isogenic mutants and clinical pairs of
Acinetobacter baumannii
isolates. Checkerboard assays and growth curves showed synergy against both colistin-susceptible strains (fractional inhibitory concentration index [FIC
index
] = 0.13 to 0.24) and colistin-resistant strains with mutations in
pmrB
and phosphoethanolamine modification of lipid A (FIC
index
= 0.14 to 0.25) but not against colistin-resistant Δ
lpx
strains with loss of lipopolysaccharide (FIC
index
= 0.75 to 1). A colistin/MD3 combination would need to be targeted to strains with specific colistin resistance mechanisms.
Mycophenolic Acid and Its Derivatives as Potential Chemotherapeutic Agents Targeting Inosine Monophosphate Dehydrogenase in Trypanosoma congolense
Authors: Suganuma Keisuke , Sarwono Albertus Eka Yudistira , Mitsuhashi Shinya , Jąkalski Marcin , Okada Tadashi , Nthatisi Molefe , Yamagishi Junya , Ubukata Makoto , Inoue Noboru
Published: May 2016

This study aimed to evaluate the trypanocidal activity of mycophenolic acid (MPA) and its derivatives for
Trypanosoma congolense
. The proliferation of
T. congolense
was completely inhibited by adding <1 μM MPA and its derivatives. In addition, the IMP dehydrogenase in
T. congolense
was molecularly characterized as the target of these compounds. The results suggest that MPA and its derivatives have the potential to be new candidates as novel trypanocidal drugs.
Chitinase 3-Like 1 (Chil1) Regulates Survival and Macrophage-Mediated Interleukin-1β and Tumor Necrosis Factor Alpha during Pseudomonas aeruginosa Pneumonia
Authors: Marion Chad R. , Wang Jianmiao , Sharma Lokesh , Losier Ashley , Lui Wei , Andrews Nathaniel , Elias Jack A. , Kazmierczak Barbara I. , Roy Craig R. , Dela Cruz Charles S.
Published: May 2016

Pseudomonas aeruginosa
causes hospital-acquired pneumonia and is associated with high mortality. An effective response to such an infection includes efficient clearance of pathogenic organisms while limiting collateral damage from the host inflammatory response, known as host resistance and host tolerance, respectively.
P. aeruginosa
expresses a type III secretion system (T3SS) needle complex that induces NLRC4 (NOD-like receptor C4) activation, interleukin-1β (IL-1β) production, and host tissue damage. Chitinase 3-like-1 (Chil1) is expressed during infection and binds to its receptor, IL-13 receptor α2 (IL-13Rα2), to regulate the pathogen-host response during
Streptococcus pneumoniae
infection, but the role Chil1 plays in balancing the host resistance and host tolerance during
P. aeruginosa
pneumonia is not known. We conducted experiments using C57BL/6 mice with or without a genetic deficiency of Chil1 and demonstrated that Chil1-deficient mice succumb to
P. aeruginosa
infection more rapidly than the wild type (WT). The decreased survival time in infected Chil1-deficient mice is associated with more neutrophils recruited to the airways, more lung parenchymal damage, and increased pulmonary consolidation while maintaining equivalent bacterial killing compared to WT mice. Infected Chil1-deficient mice and bone marrow-derived macrophages (BMDMs) from Chil1-deficient mice have increased production of tumor necrosis factor alpha (TNF-α) and IL-1β compared to infected WT mice and macrophages. Infection of Chil1-deficient BMDMs with non-NLRC4-triggering
P. aeruginosa
, which is deficient in the T3SS needle complex, did not alter the excessive IL-1β production compared to BMDMs from WT mice. The addition of recombinant Chil1 decreases the excessive IL-1β production but only partially rescues stimulated BMDMs from IL-13Rα2-deficient mice. Our data provide mechanistic insights into how Chil1 regulates
P. aeruginosa
-induced host responses.
Intergenic Variable-Number Tandem-Repeat Polymorphism Upstream of
rocA
Alters Toxin Production and Enhances Virulence in Streptococcus pyogenes
Authors: Zhu Luchang , Olsen Randall J. , Horstmann Nicola , Shelburne Samuel A. , Fan Jia , Hu Ye , Musser James M.
Published: May 2016

Variable-number tandem-repeat (VNTR) polymorphisms are ubiquitous in bacteria. However, only a small fraction of them has been functionally studied. Here, we report an intergenic VNTR polymorphism that confers an altered level of toxin production and increased virulence in
Streptococcus pyogenes
. The nature of the polymorphism is a one-unit deletion in a three-tandem-repeat locus upstream of the
rocA
gene encoding a sensor kinase.
S. pyogenes
strains with this type of polymorphism cause human infection and produce significantly larger amounts of the secreted cytotoxins
S. pyogenes
NADase (SPN) and streptolysin O (SLO). Using isogenic mutant strains, we demonstrate that deleting one or more units of the tandem repeats abolished RocA production, reduced CovR phosphorylation, derepressed multiple CovR-regulated virulence factors (such as SPN and SLO), and increased virulence in a mouse model of necrotizing fasciitis. The phenotypic effect of the VNTR polymorphism was nearly the same as that of inactivating the
rocA
gene. In summary, we identified and characterized an intergenic VNTR polymorphism in
S. pyogenes
that affects toxin production and virulence. These new findings enhance understanding of
rocA
biology and the function of VNTR polymorphisms in
S. pyogenes
.
Orbital mass secondary to infantile acute lymphoblastic leukaemia
Authors: Hossain Ibtesham Tausif , Moosajee Mariya , Abou-Rayyah Yassir , Pavasovic Vesna
Published: May 2016

An 8-month-old Asian infant girl was referred with a 1-week history of left periorbital swelling on a background of a narrowed left palpebral aperture over the preceding 8 weeks. There was no history of chronic illness, fever or other systemic features. Examination revealed a tender and fluctuant medial canthal swelling with associated periorbital haematoma. There were no other ophthalmic findings and neurological examination was normal. A MRI scan of the brain and orbit demonstrated abnormal soft tissue with features of an aggressive tumour in the left orbital region with no globe invasion. Peripheral blood smear revealed blast cells, confirmed by bone marrow aspirate. A diagnosis of infant acute lymphoblastic leukaemia was made. The patient was started on risk-stratified chemotherapy according to theInterfant-06 Protocol. The periorbital swelling resolved by day eight following a course of prednisolone, the patient continues on chemotherapy and is currently in molecular remission.
Spontaneous cutaneous extrusion of a parotid gland sialolith
Authors: Brown Kelly , Cheah Tricia , Ha Jennifer F
Published: May 2016

Parotid gland sialolithiasis is an uncommon condition that can cause pain and recurrent infection in affected patients. Migration of a stone through a fistula is a rare but possible complication of untreated sialolithiasis. We present a case of parotid gland sialolithiasis in a 63-year-old woman with recurrent episodes of parotitis and facial pain, which resolved through spontaneous extrusion of the stone (11 mm) through a cutaneous fistula while awaiting surgery. Management is typically conservative or surgical, depending on the location and size of the stone, and the clinical presentation.
Isolated right ventricular infarction: a diagnostic challenge
Authors: Vieira Catarina , Santa Cruz Andre , Arantes Carina , Rocha Sérgia
Published: May 2016

A 73-year-old woman was admitted to the emergency room due to sudden-onset dyspnoea, altered mental status and haemodynamic instability. ECG showed a junctional rhythm, T-wave inversion in I, aVL and V2-V6 (present in a previous ECG), and no ST/T changes in the right precordial leads. Transthoracic echocardiography, however, revealed a severe depression of global systolic function of right ventricle with akinesia of free wall and a normal left ventricular function. Coronary angiography showed an occlusion of the proximal segment of the right coronary artery, which was treated with balloon angioplasty, and a chronic lesion of the anterior descending artery. The patient had a good recovery and was discharged on the 14th day. Myocardial perfusion scintigraphy (stress and rest) was performed a month later, showing a fixed perfusion defect in the apex and anterior wall (medium-apical), with no signs of ischaemia.
Initial US evaluation of second-generation capsule colonoscopy for detecting colon polyps
Authors: Morgan Douglas R , Malik Pramod R , Romeo David P , Rex Douglas K
Published: May 2016

Objectives

Capsule colonoscopy is an additional screening modality for colorectal cancer. Second-generation capsule colonoscopy (CC2) may have improved efficacy in the detection of colon adenomas as compared with prior devices. The purpose of this study was to evaluate the performance of CC2 in the detection of polyps in symptomatic and screening patients in the USA.

Design

Prospective, multicentre study.

Setting and participants

Two academic medical centres and two private practice facilities, evaluating patients with indications for colonoscopy.

Methods

Patients underwent capsule colonoscopy procedure using magnesium citrate as a boost, followed by colonoscopy on the same day. The main outcome measurement was accuracy of CC2 for the detection of colorectal polyps ≥6 and ≥10 mm as compared with conventional colonoscopy.

Results

51 patients were enrolled, 50 of whom had CC2 and colonoscopy examinations and were included in the accuracy analysis. 30% and 14% of patients had polyps ≥6 and ≥10 mm, respectively. For lesions ≥10 mm identified on conventional colonoscopy, CC2 sensitivity was 100% (95% CI 56.1% to 100%) with a specificity of 93.0% (79.9% to 98.2%). For polyps ≥6 mm, the CC2 sensitivity was 93.3% (66.0% to 99.7%) and the specificity was 80.0% (62.5% to 90.9%). There was a 61% adequate cleansing rate with 64% of CC2 procedures being complete.

Conclusions

In the initial US experience with CC2 there was adequate sensitivity for detecting patients with polyps ≥6 mm in size. Magnesium citrate was inadequate as a boost agent.

Trial registration number

NCT01087528.
Cost-effectiveness of adalimumab, infliximab or vedolizumab as first-line biological therapy in moderate-to-severe ulcerative colitis
Authors: Yokomizo Lauren , Limketkai Berkeley , Park K T
Published: May 2016

Background

There are no head-to-head randomised controlled trials (RCTs) comparing the effectiveness of biologics in ulcerative colitis (UC). We aimed to assess the cost-effectiveness of adalimumab, infliximab and vedolizumab as first-line agents to induce clinical remission and mucosal healing (MH) in UC.

Methods

We constructed a decision tree based on a payer's perspective in the USA to estimate the first year costs of adalimumab, infliximab or vedolizumab to achieve clinical remission and MH in patients with moderate-to-severe UC. Transition probabilities were derived from ACT, ULTRA and GEMINI RCT data. Costs were derived from Medicare reimbursement rates and wholesale drug prices.

Results

Assuming a biological-naïve cohort, infliximab 5 mg/kg every 8 weeks was more cost-effective ($99 171 per MH achieved) than adalimumab 40 mg every other week ($316 378 per MH achieved) and vedolizumab every 8 weeks ($301 969 per MH achieved) at 1 year. Non-drug administration cost of infliximab exceeding $1974 per infusion would make adalimumab more cost-effective. First-line UC therapy with vedolizumab would be cost-effective if the drug acquisition price was <$2537 for each 300 mg administration during the 1-year time horizon.

Conclusions

If non-drug costs of infliximab administration are not excessive (<$2000), infliximab is the most cost-effective first-line biologic for moderate-to-severe UC. Exceeding this threshold infusion-related cost would make adalimumab the more cost-effective therapy. Considering its drug costs in the USA, vedolizumab appears to be appropriately used as a second-line biologic after antitumour necrosis factor failure.