bluuebunny/crossref_metadata_2025 huggingface dataset:
Augmented supraspinal fatigue following constant‐load cycling in the heat
Authors: Goodall S. , Charlton K. , Hignett C. , Prichard J. , Barwood M. , Howatson G. , Thomas K.
Published: May 2015

The development of central fatigue is prominent following exercise‐induced hyperthermia, but the contribution of supraspinal fatigue is not well understood. Seven endurance‐trained cyclists (mean ± SD peak O2 uptake, 62.0 ± 5.6 mL/kg/min) completed two high‐intensity constant‐load cycling trials (296 ± 34 W) to the limit of tolerance in a hot (34 °C, 20% relative humidity) and, on a separate occasion, for the same duration, a control condition (18 °C, 20% relative humidity). Core body temperature (Tc) was measured throughout. Before and immediately after each trial, twitch responses to supramaximal femoral nerve and transcranial magnetic stimulation were obtained from the knee extensors to assess neuromuscular and corticospinal function, respectively. Exercise time was 11.4 ± 2.6 min. Peak Tc was higher in the hot compared with control (38.36 ± 0.43 °C vs 37.86 ± 0.36 °C; P = 0.035). Post‐exercise reductions in maximal voluntary contraction force (13 ± 9% vs 9 ± 5%), potentiated twitch force (16 ± 12% vs 21 ± 13%) and voluntary activation (9 ± 7% vs 7 ± 7%) were similar in hot and control trials, respectively. However, cortical voluntary activation declined more in the hot compared with the control (8 ± 3% vs 3 ± 2%; P = 0.001). Exercise‐induced hyperthermia elicits significant central fatigue of which a large portion can be attributed to supraspinal fatigue. These data indicate that performance decrements in the heat might initially originate in the brain.
Plantar flexor neuromuscular adjustments following match‐play football in hot and cool conditions
Authors: Girard O. , Nybo L. , Mohr M. , Racinais S.
Published: May 2015

We assessed neuromuscular fatigue and recovery of the plantar flexors after playing football with or without severe heat stress. Neuromuscular characteristics of the plantar flexors were assessed in 17 male players at baseline and ∼30 min, 24, and 48 h after two 90‐min football matches in temperate (∼20 °C and 55% rH) and hot (∼43 °C and 20% rH) environments. Measurements included maximal voluntary strength, muscle activation, twitch contractile properties, and rate of torque development and soleus EMG (i.e., root mean square activity) rise from 0 to 30, −50, −100, and −200 ms during maximal isometric contractions for plantar flexors. Voluntary activation and peak twitch torque were equally reduced (−1.5% and −16.5%, respectively; P < 0.05) post‐matches relative to baseline in both conditions, the latter persisting for at least 48 h, whereas strength losses (∼5%) were not significant. Absolute explosive force production declined (P < 0.05) 30 ms after contraction onset independently of condition, with no change at any other epochs. Globally, normalized rate of force development and soleus EMG activity rise values remained unchanged. In football, match‐induced alterations in maximal and rapid torque production capacities of the plantar flexors are moderate and do not differ after competing in temperate and hot environments.
Physiological responses to incremental exercise in the heat following internal and external precooling
Authors: James C. A. , Richardson A. J. , Watt P. W. , Gibson O. R. , Maxwell N. S.
Published: May 2015

Twelve males completed three incremental, discontinuous treadmill tests in the heat [31.9(1.0) °C, 61.9(8.9)%] to determine speed at two fixed blood lactate concentrations (2 and 3.5 mmol/L), running economy (RE), and maximum oxygen uptake (). Trials involved 20 min of either internal cooling (ICE, 7.5 g/kg ice slurry ingestion) or mixed‐methods external cooling (EXT, cold towels, forearm immersion, ice vest, and cooling shorts), alongside no intervention (CON). Following precooling, participants ran 0.3 km/h faster at 2 mmol/L and 0.2 km/h faster at 3.5 mmol/L (P = 0.04, partial η2 = 0.27). Statistical differences were observed vs CON for ICE (P = 0.03, d = 0.15), but not EXT (P = 0.12, d = 0.15). There was no effect of cooling on RE (P = 0.81, partial η2 = 0.02), nor on (P = 0.69, partial η2 = 0.04). An effect for cooling on physiological strain index was observed (P < 0.01, partial η2 = 0.41), with differences vs CON for EXT (P = 0.02, d = 0.36), but not ICE (P = 0.06, d = 0.36). Precooling reduced thermal sensation (P < 0.01, partial η2 = 0.66) in both cooling groups (P < 0.01). Results indicate ICE and EXT provide similar physiological responses for exercise up to 30 min duration in the heat. Differing thermoregulatory responses are suggestive of specific event characteristics determining the choice of cooling. Precooling appears to reduce blood lactate accumulation and reduce thermoregulatory and perceptual strain during incremental exercise.
Adaptations and mechanisms of human heat acclimation: Applications for competitive athletes and sports
Authors: Périard J. D. , Racinais S. , Sawka M. N.
Published: May 2015

Exercise heat acclimation induces physiological adaptations that improve thermoregulation, attenuate physiological strain, reduce the risk of serious heat illness, and improve aerobic performance in warm‐hot environments and potentially in temperate environments. The adaptations include improved sweating, improved skin blood flow, lowered body temperatures, reduced cardiovascular strain, improved fluid balance, altered metabolism, and enhanced cellular protection. The magnitudes of adaptations are determined by the intensity, duration, frequency, and number of heat exposures, as well as the environmental conditions (i.e., dry or humid heat). Evidence is emerging that controlled hyperthermia regimens where a target core temperature is maintained, enable more rapid and complete adaptations relative to the traditional constant work rate exercise heat acclimation regimens. Furthermore, inducing heat acclimation outdoors in a natural field setting may provide more specific adaptations based on direct exposure to the exact environmental and exercise conditions to be encountered during competition. This review initially examines the physiological adaptations associated with heat acclimation induction regimens, and subsequently emphasizes their application to competitive athletes and sports.
Isothermic and fixed‐intensity heat acclimation methods elicit equal increases in Hsp72 mRNA
Authors: Gibson O. R. , Mee J. A. , Taylor L. , Tuttle J. A. , Watt P. W. , Maxwell N. S.
Published: May 2015

Thermotolerance, to which heat shock protein‐72 (Hsp72) contributes, is an acquired state achieved following heat acclimation (HA), eliciting cellular adaption and protection against thermal stress. Optimal HA methods achieving the greatest heat shock response (HSR) are equivocal; therefore, investigation of methods provoking the greatest sustained HSR is required to optimize cellular adaptation. Twenty‐four males performed short‐term HA (STHA; five sessions) and long‐term HA (LTHA; STHA plus further five sessions) utilizing fixed‐intensity (FIXED; workload = 50% ), continuous isothermic HA [ISOCONT; target rectal temperature (Trec) = 38.5 °C], or progressive isothermic HA (ISOPROG; target Trec = 38.5 °C for STHA then target Trec = 39.0 °C for LTHA). Leukocyte Hsp72 mRNA was measured pre‐ and post day 1, day 5, and day 10 of HA via reverse transcription quantitative polymerase chain reaction to determine the HSR. Hsp72 mRNA increased (P < 0.05) pre‐ to post day 1, pre‐ to post day 5, and pre to post day 10 in FIXED, ISOCONT, and ISOPROG, but no differences were observed between methods (P > 0.05). The equal Hsp72 mRNA increases occurring from consistent, reduced, or increased endogenous strain following STHA and LTHA suggest that transcription occurs following attainment of sufficient endogenous criteria. These data give confidence that all reported HA methods increase Hsp72 mRNA and are capable of eliciting adaptations toward thermotolerance.
Sprint performance under heat stress: A review
Authors: Girard O. , Brocherie F. , Bishop D. J.
Published: May 2015

Training and competition in major track‐and‐field events, and for many team or racquet sports, often require the completion of maximal sprints in hot (>30 °C) ambient conditions. Enhanced short‐term (<30 s) power output or single‐sprint performance, resulting from transient heat exposure (muscle temperature rise), can be attributed to improved muscle contractility. Under heat stress, elevations in skin/core temperatures are associated with increased cardiovascular and metabolic loads in addition to decreasing voluntary muscle activation; there is also compelling evidence to suggest that large performance decrements occur when repeated‐sprint exercise (consisting of brief recovery periods between sprints, usually <60 s) is performed in hot compared with cool conditions. Conversely, poorer intermittent‐sprint performance (recovery periods long enough to allow near complete recovery, usually 60–300 s) in hotter conditions is solely observed when exercise induces marked hyperthermia (core temperature >39 °C). Here we also discuss strategies (heat acclimatization, precooling, hydration strategies) employed by “sprint” athletes to mitigate the negative influence of higher environmental temperatures.
Time course of natural heat acclimatization in well‐trained cyclists during a 2‐week training camp in the heat
Authors: Karlsen A. , Nybo L. , Nørgaard S. J. , Jensen M. V. , Bonne T. , Racinais S.
Published: May 2015

The aim of this study was to determine the time course of physiological adaptations and their relationship with performance improvements during 2 weeks of heat acclimatization. Nine trained cyclists completed 2 weeks of training in naturally hot environment (34 ± 3 °C; 18 ± 5% relative humidity). On days 1, 6, and 13, they performed standardized heat response tests (HRT‐1, 2, 3), and 43.4‐km time trials in the heat (TTH‐1, 2, 3) were completed on days 2, 7, and 14. Within the first 5–6 days, sweat sodium concentration decreased from 75 ± 22 mmol/L to 52 ± 24 mmol/L, sweat rate increased (+20 ± 15%), and resting hematocrit decreased (−5.6 ± 5.4%), with no further changes during the remaining period. In contrast, power output during TTHs gradually improved from TTH‐1 to TTH‐2 (+11 ± 8%), and from TTH‐2 to TTH‐3 (+5 ± 4%). Individual improvements in performance from TTH‐1 to TTH‐2 correlated with individual changes in hematocrit (assessed after the corresponding HRT; r = −0.79, P < 0.05), however, were not related to changes in performance from TTH‐2 to TTH‐3. In trained athletes, sudomotor and hematological adaptations occurred within 5–6 days of training, whereas the additional improvement in performance after the entire acclimatization period did not relate to changes in these parameters.
Consensus recommendations on training and competing in the heat
Authors: Racinais S. , Alonso J. M. , Coutts A. J. , Flouris A. D. , Girard O. , González‐Alonso J. , Hausswirth C. , Jay O. , Lee J. K. W. , Mitchell N. , Nassis G. P. , Nybo L. , Pluim B. M. , Roelands B. , Sawka M. N. , Wingo J. E. , Périard J. D.
Published: May 2015

Exercising in the heat induces thermoregulatory and other physiological strain that can lead to impairments in endurance exercise capacity. The purpose of this consensus statement is to provide up‐to‐date recommendations to optimize performance during sporting activities undertaken in hot ambient conditions. The most important intervention one can adopt to reduce physiological strain and optimize performance is to heat acclimatize. Heat acclimatization should comprise repeated exercise‐heat exposures over 1–2 weeks. In addition, athletes should initiate competition and training in a euhydrated state and minimize dehydration during exercise. Following the development of commercial cooling systems (e.g., cooling vest), athletes can implement cooling strategies to facilitate heat loss or increase heat storage capacity before training or competing in the heat. Moreover, event organizers should plan for large shaded areas, along with cooling and rehydration facilities, and schedule events in accordance with minimizing the health risks of athletes, especially in mass participation events and during the first hot days of the year. Following the recent examples of the 2008 Olympics and the 2014 FIFA World Cup, sport governing bodies should consider allowing additional (or longer) recovery periods between and during events for hydration and body cooling opportunities when competitions are held in the heat.
Effects of Defending: The Longitudinal Relations Among Peer‐perceived Defending of Victimized Peers, Victimization, and Liking
Authors: Meter Diana J. , Card Noel A.
Published: May 2015

Previous research has shown victims of peer aggression to be positively impacted by being defended by peers, but how enacted defending impacts defenders themselves is not thoroughly understood. In this study, the longitudinal associations between peer‐perceived liking, enacted defending, and defender's own victimization were investigated among 336 adolescents (M age = 13.21 years). Peer perceived liking was expected to predict defending. It was also hypothesized that a reputation for defending victimized peers would be related to being perceived as less victimized and more liked over time. Results showed that peer perceived liking was not predictive of defending. Enacted defending was associated with a decrease in victimization over time, but also a decrease in peer‐perceived liking. Defenders may benefit from enacted defending by decreasing their own victimization, but this benefit is nuanced.
Measuring Anti‐Trafficking Policy—Integrating Text and Statistical Analyses
Authors: Cho Seo‐Young
Published: May 2015

Objectives

The objectives of this article are to review existing indices on anti‐trafficking policy and to propose a way to improve the policy indices.

Methods

The four existing indices—the 3P Index, the GRETA‐based Scorecard, the EuroStat, and the U.S. Tier‐Ranking—were compared regarding their contents, quantification methods, and the coverage of the data. In particular, the validity of the first two indices coded from qualitative information was examined through tests for linear correlation, and the content of the EuroStat was evaluated by multicovariate regression analyses.

Results

Empirical results show that the evaluation outcomes of the 3P Index and the Scorecard are considerably different, arguably because of the noncomprehensive selection of policy requirments and subjective judgments in interpreting qualitative texts. On the other hand, EuroStat seems to measure the quality of anti‐trafficking policy and therefore these statistics can be used as relevant indicators of policy evaluation.

Conclusion

The empirical investigation of this article suggests that integrating textual and statistical information can be a way to improve the quality of an index evaluating anti‐trafficking policy.
A Novel Class of Strain Measures for Digital Image Correlation
Authors: Lehoucq R. B. , Reu P. L. , Turner D. Z.
Published: May 2015

We propose a novel class strain measures for use with digital image correlation (DIC). Whereas the traditional notion of compatibility (strain as the derivative of the displacement field) is problematic when the displacement field varies substantially because of either measurement noise or material irregularity, the proposed measure remains robust, well defined and invariant under rigid body motion. Moreover, when the displacement field is smooth, the classical and proposed strain measures are approximations of each other. We demonstrate, via several numerical examples, the potential of this new strain measure for problems with steep gradients. We also show how the non‐local strain provides an intrinsic mechanism for filtering high‐frequency content from the strain profile and so has a high signal to noise ratio. This is a convenient feature considering image noise and its impact on strain calculations.
H2A.Z mediates different aspects of chromatin function and modulates flowering responses in Arabidopsis
Authors: Jarillo José A. , Piñeiro Manuel
Published: May 2015

Eukaryotic organisms have canonical histones and a number of histone variants that perform specialized functions and confer particular structural properties to the nucleosomes that contain them. The histone H2A family comprises several variants, with H2A.Z being the most evolutionarily conserved. This variant is essential in eukaryotes and has emerged as a key player in chromatin function, performing an essential role in gene transcription and genome stability. During recent years, biochemical, genetic and genomic studies have begun to uncover the role of several ATP‐dependent chromatin‐remodeling complexes in H2A.Z deposition and removal. These ATPase complexes are widely conserved from yeast to mammals. In Arabidopsis there are homologs for most of the subunits of these complexes, and their functions are just beginning to be unveiled. In this review, we discuss the major contributions made in relation to the biology of the H2A.Z in plants, and more specifically concerning the function of this histone variant in the transition from vegetative to reproductive development. Recent advances in the understanding of the molecular mechanisms underlying the H2A.Z‐mediated modulation of the floral transition, and thermosensory flowering responses in particular, are discussed. The emerging picture shows that plants contain chromatin‐remodeling complexes related to those involved in modulating the dynamics of H2A.Z in other eukaryotes, but their precise biochemical nature remains elusive.
Microangiographic Comparison of the Effects of 3 Loop Pulley and 6 Strand Savage Tenorrhaphy Techniques on Equine Superficial Digital Flexor Tendon
Authors: Freeman Kendra D. , Barrett Jennifer G. , Youngstrom Daniel W. , White Nathaniel A.
Published: May 2015

Objective

The 6‐strand Savage (SSS) tenorrhaphy pattern is biomechanically superior to the commonly employed 3‐loop pulley (3LP); however, its effects on intrinsic tendon vasculature remain unknown. The objective of this study was to compare perfusion of intrinsic vasculature of the equine superficial digital flexor tendon (SDFT) after 3LP and SSS tenorrhaphies. We hypothesized that the SSS technique would significantly decrease vascular perfusion compared to the 3LP technique.

Study Design

Ex vivo, randomized, paired design.

Animals

Horses (n = 9)

Methods

Under general anesthesia, 9 pairs of forelimb SDFT were transected. Two tendons served as baseline control, the remainder had either SSS or 3LP tenorrhaphy performed. Horses were heparinized, euthanatized, and forelimbs perfused with barium sulfate solution were then fixed with formalin under tension. Tendons were transected every 5 mm and microangiographic images obtained. Microvascular analysis of sections proximal to, throughout, and distal to the tenorrhaphy was completed using a custom macro. Differences in vascular count were assessed using MANOVA.

Results

A significant reduction in the number of perfused vessels was seen for SSS compared with 3LP at 2 locations within the tenorrhaphy (P = .039 andP = .009). The SSS technique took on average 4.7 ± 0.9 times longer to place.

Conclusions

The SSS technique causes an acute reduction in tendon perfusion compared to the 3LP, which may limit its clinical use. Further research is required to elucidate the clinical significance of this difference.
Suture‐Free Ureterovesical Anastomosis Using a Microvascular Anastomosis System: Canine Cadaveric Study
Authors: Bertran Judith , Wavreille Vincent A. , Ham Kathleen L. , McLoughlin Mary A. , Adin Christopher A.
Published: May 2015

Objective

To describe a suture‐free ureterovesical anastomosis using a microvascular anastomotic system (MAS) and compare the surgical time and bursting pressure to a sutured ureterovesical anastomosis (SA) with and without an extravesical seromuscular tunnel (EVSMT).

Study Design

Randomized, unblocked design, ex vivo study.

Animals

Three canine cadavers.

Methods

For each cadaver, the ureters were sectioned into 3 equal lengths. The 6 sections were randomly assigned to receive either the MAS or end‐side SA. The first cadaver (3 MAS, 3 SA) was used to refine the technique, and the remaining 2 cadavers were used for evaluation. Surgical time and bursting pressure of the anastomosis were compared between MAS and SA (n = 6 per technique). After bursting pressure testing of each anastomosis, an SMT was created over the anastomoses. Bursting pressures were again recorded and compared across techniques.

Results

The surgery time was significantly shorter for MAS (median 5.4 minutes) than SA (median 15.8 minutes;P = .002). The bursting pressure was significantly higher for MAS (median 189.5 cmH2O) than SA (median 64 cmH2O;P = .002). The bursting pressure for MAS‐EVSMT (median 398.5 cmH2O) was not significantly different from the SA‐EVSMT (median 321 cmH2O,P = .567); however, the creation of an SMT significantly increased the bursting pressure for both techniques (P = .028, respectively).

Conclusion

This study demonstrated the feasibility of a suture‐free ureterovesical anastomosis in the canine cadaver using a commercially available MAS. The MAS anastomosis was faster and resulted in higher bursting pressures than SA. The creation of an SMT improved the bursting resistance of both techniques but there was no difference between the techniques covered by an EVSMT.
Fractalkine neutralization improves cardiac function after myocardial infarction
Authors: Gu Xiaosong , Xu Jiang , Yang Xiao‐Ping , Peterson Edward , Harding Pamela
Published: May 2015

New Findings

What is the central question of this study?

What is the cardioprotective role of fractalkine neutralization in heart failure and what are the mechanisms responsible?

What is the main finding and its importance?

The concentration of fractalkine is increased in the left ventricle of mice with myocardial infarction, similar to the increases in plasma from heart failure patients. The present study shows a clear beneficial effect of neutralizing fractalkine in a model of myocardial infarction, which results in increased survival. Such an approach may be worthwhile in human patients.

Concentrations of the chemokine fractalkine (FKN) are increased in patients with chronic heart failure, and our previous studies show that aged mice lacking the prostaglandin E2 EP4 receptor subtype (EP4‐KO) have increased cardiac FKN, with a phenotype of dilated cardiomyopathy. However, how FKN participates in the pathogenesis of heart failure has rarely been studied. We hypothesized that FKN contributes to the pathogenesis of heart failure and that anti‐FKN treatment prevents heart failure induced by myocardial infarction (MI) more effectively in EP4‐KO mice. Male EP4‐KO mice and wild‐type littermates underwent sham or MI surgery and were treated with an anti‐FKN antibody or control IgG. At 2 weeks post‐MI, echocardiography was performed and hearts were excised for determination of infarct size, immunohistochemistry and Western blot of signalling molecules. Given that FKN protein levels in the left ventricle were increased to a similar extent in both strains after MI and that anti‐FKN treatment improved survival and cardiac function in both strains, we subsequently used only wild‐type mice to examine the mechanisms whereby anti‐FKN is cardioprotective. Myocyte cross‐sectional area and interstitial collagen fraction were reduced after anti‐FKN treatment, as were macrophage migration and gelatinase activity. Activation of ERK1/2 and p38 MAPK were reduced after neutralization of FKN. In vitro, FKN increased fibroblast proliferation. In conclusion, increased FKN contributes to heart failure after MI. This effect is not exacerbated in EP4‐KO mice, suggesting that there is no link between FKN and lack of EP4. Overall, inhibition of FKN may be important to preserve cardiac function post‐MI.
Novel method to improve transdermal drug delivery by atmospheric microplasma irradiation
Authors: Shimizu Kazuo , Hayashida Kentaro , Blajan Marius
Published: May 2015

Application of atmospheric plasma could be used for wound healing, skin rejuvenation, and wrinkle treatment. The authors explored the feasibility of atmospheric microplasma irradiation (AMI) for enhancement of percutaneous absorption of drugs as an alternative to hypodermic needles. Pig skin was used as a biological sample exposed to AMI and analyzed by attenuated total reflection-Fourier transform infrared spectroscopy. A tape-stripping test (an evaluation method for skin-barrier performance) was also conducted to compare with AMI. Transepidermal water loss was also measured and compared with and without AMI. Results showed that surface modification of the stratum corneum (outermost skin layer) was observed upon AMI. Small pores on sample skin were observed with plasma jet irradiation due to the collision of charged particles. Percutaneous absorption was confirmed without damage upon microplasma irradiation. Our data suggested that dye pathways through skin samples could be related to the dynamic behavior of intercellular lipid bilayers, suggesting that AMI could enhance percutaneous absorption.
Nanostructured thin films for hydrogen-permeation barrier
Authors: Tamura Motonori , Eguchi Takashi
Published: May 2015

The authors confirmed that applying a coating of Al2O3, TiC, or TiN on a substrate reduced the hydrogen permeation by a factor of at least one order of magnitude compared with uncoated substrates. Al2O3 films consisting of fine crystal grains, with diameters of about 40 nm or less, provided superior hydrogen-permeation barriers on the test specimens. The test specimens coated with TiN or TiC films, with columnar crystals grown vertically on the substrate, tended to exhibit higher hydrogen permeability. The microcrystalline structures with many grain boundaries are expected to provide effective hydrogen-barrier performance.
In situ electrochemical study of the interaction of cells with thermally treated titanium
Authors: Burgos-Asperilla Laura , Fierro Jose Luis Garcia , Gamero Miriam , Escudero Maria Lorenza , Alonso Concepción , García-Alonso Maria Cristina
Published: May 2015

Micromotion and fretting wear between bone and Ti-based alloys in stem and dental implants breaks the passive film and exposes the metal to the action of the complex surrounding medium, generating substantial amounts of debris and continuous Ti ion release. In this work, oxidation treatments at low temperatures (277 °C, 5 h) have been used to promote the formation of wear-corrosion resistant titanium oxide on the Ti surface. The objective of this paper has been the study of the influence of live cells on the protectiveness of the oxide formed at these low temperatures. The interaction of cells with the modified surface has been studied by scanning electron microscopy, electrochemical impedance spectroscopy, polarization curves, and x-ray photoelectron spectroscopy (XPS). The chemical composition of the thermally treated Ti surface is mainly TiO2 as anatase-rich titanium dioxide with a low concentration of hydroxyl groups and a low mean nanoroughness that could promote good cell adhesion. The electrochemical results indicate that the cells alter the overall resistance of the thermally treated Ti surfaces by decreasing the oxide resistance with time. At the same time, the anodic current increases, which is associated with cathodic control, and is probably due to the difficulty of access of oxygen to the Ti substrate. XPS reveals the presence of proteins on the surface of the treated specimens in contact with the cells and a decrease in the Ti signal associated with the extracellular matrix on the surface and the reduction of the oxide thickness.
Spectral overlap and interaural time difference sensitivity: Possible role of binaural interference
Authors: Brown Christopher A. , Yost William A.
Published: May 2015

A follow-up experiment to those conducted by Brown and Yost [(2011). J. Acoust. Soc. Am. 130, 358–364; (2013). Basic Aspects of Hearing: Physiology and Perception (Springer, London, UK)] examined interaural time difference (ITD) discrimination for a low-frequency target noise band flanked by monotic noise bands that were either lower-frequency than the target band, higher-frequency, or both. The flanking bands were either spectrally contiguous with the target band or spectrally separated. Significant interference in ITD processing occurred in the presence of the high-frequency flanking band. Results are discussed by way of a comparison of the conditions in the present study to those in studies of binaural interference. The possible role of attention is also discussed.
Biomimetic direction of arrival estimation for resolving front-back confusions in hearing aids
Authors: Archer-Boyd Alan W. , Whitmer William M. , Brimijoin W. Owen , Soraghan John J.
Published: May 2015

Sound sources at the same angle in front or behind a two-microphone array (e.g., bilateral hearing aids) produce the same time delay and two estimates for the direction of arrival: A front-back confusion. The auditory system can resolve this issue using head movements. To resolve front-back confusion for hearing-aid algorithms, head movement was measured using an inertial sensor. Successive time-delay estimates between the microphones are shifted clockwise and counterclockwise by the head movement between estimates and aggregated in two histograms. The histogram with the largest peak after multiple estimates predicted the correct hemifield for the source, eliminating the front-back confusions.
Acoustic Rayleigh scattering in water-saturated granular medium with quasicrystalline approximation
Authors: Lee Keunhwa , Yang Haesang , Seong Woojae
Published: May 2015

A closed-form solution for the effective wavenumber in a water-saturated medium as a function of the Rayleigh parameter is derived up to the second leading terms in the real part and first leading term in the imaginary part. This is based on the Waterman multiple scattering formulation with the quasicrystalline approximation (QCA) and the Percus–Yevick pair-correlation function. The formula's resultant sound speed and attenuation are compared to the regression relation matching the measurements in the Rayleigh scattering region [Kimura, J. Acoust. Soc. Am. 129(6), 3544–3561 (2011)]. The sound speeds are comparable. However, for the attenuation, it is shown that the QCA result underestimates the measured attenuation while its behavior exhibits similar frequency dependency of f4.
Comparison in Joint-Position Sense and Muscle Coactivation Between Anterior Cruciate Ligament–Deficient and Healthy Individuals
Authors: Suarez Tania , Laudani Luca , Giombini Arrigo , Saraceni Vincenzo Maria , Mariani Pier Paolo , Pigozzi Fabio , Macaluso Andrea
Published: May 2015

Context:

Tearing of the anterior cruciate ligament (ACL) may disrupt the ability to recognize the knee position in space during limb-repositioning tasks, which is referred to as joint-position sense (JPS). Impairments in JPS have been shown to be lower during active than passive repositioning tasks, thus suggesting that coactivation patterns of the muscles surrounding the knee might compensate for the disrupted JPS and ensure accurate limb repositioning in ACL-deficient individuals.

Objective:

To investigate muscle coactivation patterns during JPS repositioning tasks in ACL-deficient and healthy individuals.

Design:

Prospective observational study.

Setting:

Functional assessment laboratory.

Participants:

8 men age 25 ± 8 y with isolated ACL rupture and 10 men age 30 ± 4 y with no history of knee injury.

Intervention:

JPS was evaluated by means of an electrogoniometer in a sitting position during either passive or active joint-positioning and -repositioning tasks with a 40° target knee angle.

Main Outcome Measures:

Root mean square (RMS) of the surface electromyogram from the vastus lateralis and biceps femoris muscles was measured during active joint positioning and repositioning.

Results:

Healthy participants showed a significant decrease in vastus lateralis RMS (−19%) and an increase in biceps femoris RMS (+26%) during joint repositioning compared with positioning. In contrast, ACL-deficient patients showed no modulation in muscle coactivation between joint positioning and repositioning, although they exhibited significantly lower RMS of the vastus lateralis (injured limb, −28%; uninjured limb, −21%) and higher RMS of the biceps femoris (injured limb, +19%; uninjured limb, +30%) than the healthy participants during joint positioning.

Conclusions:

The lack of modulation in muscle coactivation patterns between joint positioning and repositioning in ACL-deficient patients might be attributed to disrupted neural control after the injury-related loss of proprioceptive information. These results should be taken into account in the design of rehabilitation protocols with emphasis on muscle coactivation and JPS.
Can a Single-Leg Squat Provide Insight into Movement Control and Loading During Dynamic Sporting Actions in Patients With Athletic Groin Pain?
Authors: Marshall Brendan M. , Franklyn-Miller Andrew D. , Moran Kieran A. , King Enda A. , Strike Siobhán C. , Falvey Éanna C
Published: May 2015

Context:

Chronic athletic groin pain (AGP) is common in field sports and has been associated with abnormal movement control and loading of the hip and pelvis during play. A single-leg squat (SLS) is commonly used by clinicians to assess movement control, but whether it can provide insight into control during more dynamic sporting movements in AGP patients is unclear.

Objective:

To determine the relationships between biomechanical measures in an SLS and the same measures in a single-leg drop landing, single-leg hurdle hop, and a cutting maneuver in AGP patients.

Design:

Cross-sectional study.

Setting:

Biomechanics laboratory.

Patients:

40 recreational field-sports players diagnosed with AGP.

Intervention:

A biomechanical analysis of each individual’s SLS, drop landing, hurdle hop, and cut was undertaken.

Main Outcome Measures:

Hip, knee, and pelvis angular displacement and hip and knee peak moments. Pearson product–moment correlations were used to examine relationships between SLS measures and equivalent measures in the other movements.

Results:

There were no significant correlations between any hip or pelvis measure in the SLS with the same measures in the drop landing, hurdle hop, or cut (r = .03–.43, P > .05). Knee frontal- and transverse-plane angular displacement were related in the SLS and drop landing only, while knee moments were related in the SLS, drop-landing, and hurdle hop (r = .50–.67, P < .05).

Conclusion:

For AGP patients, an SLS did not provide meaningful insight into hip and pelvis control or loading during sporting movements that are associated with injury development. The usefulness of an SLS test in the assessment of movement control and loading in AGP patients is thus limited. The SLS provided moderate insight into knee control while landing and therefore may be of use in the examination of knee-injury risk.
The Effect of Kinesio Taping on Anterior Knee Pain Consistent With Patellofemoral Pain Syndrome: A Critically Appraised Topic
Authors: Campbell Samantha A. , Valier Alison R.
Published: May 2015

Clinical Scenario:

Patellofemoral pain syndrome (PFPS) occurs in 25% of adolescents and adults and is the leading cause of knee pain in runners. Pain is commonly felt when ascending or descending stairs, deep squatting, kneeling, or running. There is no consensus on the etiology of this condition, but insufficient hip strength, malalignment of the lower extremity, hyperpronation of the foot, and patellar incongruence have been suggested. Common treatments of PFPS include strengthening of quadriceps and hip muscles, McConnell taping, electrical stimulation, and foot orthotics, but effectiveness of these treatments is inconclusive. Kinesio Taping is an alternative taping technique for musculoskeletal injuries including PFPS. Although research suggests that Kinesio Taping decreases pain and improves range of motion for some musculoskeletal injuries, its effectiveness in decreasing pain in patients with PFPS in unknown. Furthermore, Kinesio Taping has not been compared with other taping techniques including McConnell taping.

Focused Clinical Question:

For patients with anterior knee pain consistent with PFPS, does treatment with Kinesio Taping decrease pain more than McConnell taping or no tape at all?
Does a Reduction in Serum Sodium Concentration or Serum Potassium Concentration Increase the Prevalence of Exercise-Associated Muscle Cramps?
Authors: Murray Donal , Miller Kevin C. , Edwards Jeffrey E.
Published: May 2015

Clinical Scenario:

Although exercise-associated muscle cramps (EAMC) are common in ultradistance runners and athletes in general, their etiology remains unclear. EAMC are painful, sudden, involuntary contractions of skeletal muscle occurring during or after exercise and are recognized by visible bulging or knotting of the whole, or part of, a muscle. Many clinicians believe EAMC occur after an imbalance in electrolyte concentrations, specifically serum sodium concentration ([Na+]s) and serum potassium concentration ([K+]s). Studies that have established a link between EAMC occurrence and serum electrolyte concentrations after an athletic event are unhelpful.

Focused Clinical Question:

Are [Na+]s and [K+]s different in athletes who experience EAMC than noncrampers?
Lower-Limb Muscle-Activation Patterns During Off-Axis Elliptical Compared With Conventional Gluteal-Muscle-Strengthening Exercises
Authors: Lin Cindy Y. , Tsai Liang-Ching , Press Joel , Ren Yupeng , Chung Sun G. , Zhang Li-Qun
Published: May 2015

Context:

Gluteal-muscle strength has been identified as an important component of injury prevention and rehabilitation in several common knee injuries. However, many conventionally prescribed gluteal-strengthening exercises are not performed during dynamic weight-bearing activities, which is when most injuries occur.

Objectives:

To compare lower-limb muscle-activation patterns between conventional gluteal-strengthening exercises and off-axis elliptical exercises with motorized foot-plate perturbations designed to activate gluteal muscles during dynamic exercise.

Evidence Acquisition:

Twelve healthy volunteers (26.1 ± 4.7 y) participated in the study. They performed 3 conventional exercises (single-leg squat, forward lunge, and clamshell) and 3 elliptical exercises (regular, while resisting an adduction force, and while resisting an internal-rotation torque). Gluteus medius (GMed) and maximus (GMax), quadriceps, hamstrings, and gastrocnemius muscle activations during each exercise were recorded using surface electromyography (EMG) and normalized to maximal voluntary isometric contraction (MVIC).

Evidence Synthesis:

Normalized GMed EMG was the highest during the adduction-resistance elliptical exercise (22.4% ± 14.8% MVIC), significantly greater than forward lunge (8.2% ± 3.8% MVIC) and regular elliptical (6.4% ± 2.5% MVIC) and similar to clamshell (19.1% ± 8.8% MVIC) and single-leg squat (18.4% ± 7.9% MVIC). Normalized GMax EMG during adduction-resistance (11.1% ± 7.6% MVIC) and internal-rotation-resistance elliptical (7.4% ± 3.8% MVIC) was significantly greater than regular elliptical (4.4% ± 2.4% MVIC) and was similar to conventional exercises. The single-leg squat required more muscle activation from the quadriceps and gastrocnemius than the elliptical exercises.

Conclusions:

Off-axis elliptical exercise while resisting an adduction force or internal-rotation torque activates gluteal muscles dynamically while avoiding excessive quadriceps activation during a functional weight-bearing activity compared with conventional gluteal-strengthening exercises.
Identification of a plant isoflavonoid that causes biliary atresia
Authors: Lorent Kristin , Gong Weilong , Koo Kyung A. , Waisbourd-Zinman Orith , Karjoo Sara , Zhao Xiao , Sealy Ian , Kettleborough Ross N. , Stemple Derek L. , Windsor Peter A. , Whittaker Stephen J. , Porter John R. , Wells Rebecca G. , Pack Michael
Published: May 2015

A plant toxin with a previously uncharacterized chemical structure causes biliary atresia in zebrafish and mammals.
AAV and gene therapy: It’s complicated
Authors: Dalkara Deniz
Published: May 2015

AAV capsid preference toward cell-surface receptors determines not just its tissue specificity but also plays a key role in immune activation.
Out of reach
Authors: Lalazar Gadi
Published: May 2015

A liver-specific mechanism of effector CD8
+
T cell immune surveillance is inhibited by liver fibrosis.
Culturing Life from Air: Using a Surface Air System to Introduce Discovery-Based Research in Aerobiology into the Undergraduate Biology Curriculum
Authors: Weber Carolyn F. , Werth Jason T.
Published: May 2015

Although the field of aerobiology predates Louis Pasteur’s classic experiments in the late 19th century, the atmosphere has recently emerged as one of the last great frontiers in the field of microbiology. Recent research has demonstrated that airborne microbes are more diverse than previously thought and are metabolically active in some cases, influencing atmospheric chemistry and meteorological patterns. Furthermore, concern continues to grow regarding airborne travel of biothreat agents and emerging infectious diseases in an increasingly global society. Despite the increased recognition of the atmosphere as a frontier for microbiological exploration in both basic and applied sciences, students are generally not exposed to this field of research in the undergraduate biology curriculum. We describe the use of the Surface Air System (SAS) SUPER 180 (Bioscience International, Rockville, MD), an extremely rugged, easy-to-use, portable and nearly maintenance-free instrument that impacts defined volumes of air directly onto petri dishes to facilitate the study of culturable airborne microorganisms. We successfully employed this instrument in a Biology I course in which freshmen, with no prior research experiences, conducted discovery-based research that produced data that was presented at a national meeting and made a genuine contribution to the field of aerobiology. We also describe how such discovery-based research experiences in aerobiology can be used as a platform for teaching core biological concepts and basic laboratory skills.

Editor's Note:
The ASM advocates that students must successfully demonstrate the ability to explain and practice safe laboratory techniques. For more information, read the laboratory safety section of the ASM Curriculum Recommendations: Introductory Course in Microbiology and the Guidelines for Biosafety in Teaching Laboratories, available at www.asm.org. The Editors of JMBE recommend that adopters of the protocols included in this article follow a minimum of Biosafety Level 2 practices.
When Do Students “Learn-to-Comprehend” Scientific Sources?: Evaluation of a Critical Skill in Undergraduates Progressing through a Science Major
Authors: Marsh Tamara L. , Guenther Merrilee F. , Raimondi Stacey L.
Published: May 2015

In response to the publication of Vision and Change, the biology department at Elmhurst College revised our curriculum to better prepare students for a career in science with the addition of various writing assignments in every course. One commonality among all of the assignments is the ability to comprehend and critically evaluate scientific literature to determine relevancy and possible future research. Several previous reports have analyzed specific methodologies to improve student comprehension of scientific writing and critical thinking skills, yet none of these examined student growth over an undergraduate career. In this study, we hypothesized upper-level students would be better able to comprehend and critically analyze scientific literature than introductory biology majors. Biology students enrolled in an introductory (200-level), mid- (300-level), or late-career (400-level) course were tasked with reading and responding to questions regarding a common scientific article and rating their comfort and confidence in reading published literature. As predicted, upper-level (mid- and late-career) students showed increases in comprehension and critical analysis relative to their first-year peers. Interestingly, we observed that upper-level students read articles differently than introductory students, leading to significant gains in understanding and confidence. However, the observed gains were modest overall, indicating that further pedagogical change is necessary to improve student skills and confidence in reading scientific articles while fulfilling the Vision and Change recommendations.
The HeLa Documentary Film: An Engaging Writing and Culturally Relevant Assignment on Cell Division and Ethics for Nonscience Majors
†
Authors: Jordan Diann , Bonds Timetria
Published: May 2015

Historically black institutions play a pivotal role in educating the next generation of scientists and engineers as well as promoting scientific literacy among all of its students. Students would like to have more culturally relevant assignments that reflect their life experiences as it relates to course content. We used the HeLa documentary film, "The Way of All Flesh Film," as an effective teaching tool in the first survey course of general biology to supplement our discussion on the cell cycle and ethics in scientific studies. Over 90% of our students preferred this additional teaching method compared to a traditional lecture only. Furthermore, the exercise enhanced the students' writing, research, and critical thinking skills through the ethical implications of the film.
Facilitating Improvements in Laboratory Report Writing Skills with Less Grading: A Laboratory Report Peer-Review Process
Authors: Brigati Jennifer R. , Swann Jerilyn M.
Published: May 2015

Incorporating peer-review steps in the laboratory report writing process provides benefits to students, but it also can create additional work for laboratory instructors. The laboratory report writing process described here allows the instructor to grade only one lab report for every two to four students, while giving the students the benefits of peer review and prompt feedback on their laboratory reports. Here we present the application of this process to a sophomore level genetics course and a freshman level cellular biology course, including information regarding class time spent on student preparation activities, instructor preparation, prerequisite student knowledge, suggested learning outcomes, procedure, materials, student instructions, faculty instructions, assessment tools, and sample data.
T
-tests comparing individual and group grading of the introductory cell biology lab reports yielded average scores that were not significantly different from each other (
p
= 0.13, n = 23 for individual grading, n = 6 for group grading).
T
-tests also demonstrated that average laboratory report grades of students using the peer-review process were not significantly different from those of students working alone (
p
= 0.98, n = 9 for individual grading, n = 6 for pair grading). While the grading process described here does not lead to statistically significant gains (or reductions) in student learning, it allows student learning to be maintained while decreasing instructor workload. This reduction in workload could allow the instructor time to pursue other high-impact practices that have been shown to increase student learning. Finally, we suggest possible modifications to the procedure for application in a variety of settings.