bluuebunny/crossref_metadata_2025 huggingface dataset:
Fault Diagnosis of Rolling Bearings Using Data Mining Techniques and Boosting
Authors: Unal Muhammet , Sahin Yusuf , Onat Mustafa , Demetgul Mustafa , Kucuk Haluk
Published: September 2016

Rolling bearings are key components in most mechanical facilities; hence, the diagnosis of their faults is very important in predictive maintenance. Up to date, vibration analysis has been widely used for fault diagnosis in practice. However, acoustic analysis is still a novel approach. In this study, acoustic analysis with classification is used for fault diagnosis of rolling bearings. First, Hilbert transform (HT) and power spectral density (PSD) are used to extract features from the original sound signal. Then, decision tree algorithm C5.0, support vector machines (SVMs) and the ensemble method boosting are used to build models to classify the instances for three different classification tasks. Performances of the classifiers are compared w.r.t. accuracy and receiver operating characteristic (ROC) curves. Although C5.0 and SVM show comparable performances, C5.0 with boosting classifier indicates the highest performance and perfectly discriminates normal instances from the faulty ones in each task. The defect sizes to create faults used in this study are notably small compared to previous studies. Moreover, fault diagnosis is done for rolling bearings operating at different loading conditions and speeds. Furthermore, one of the classification tasks incorporates diagnosis of five states including four different faults. Thus, these models, due to their high performance in classifying multiple defect scenarios having different loading conditions and speeds, can be readily implemented and applied to real-life situations to detect and classify even incipient faults of rolling bearings of any rotating machinery.
Measurement Techniques for Thermal Conductivity and Interfacial Thermal Conductance of Bulk and Thin Film Materials
Authors: Zhao Dongliang , Qian Xin , Gu Xiaokun , Jajja Saad Ayub , Yang Ronggui
Published: September 2016

Thermal conductivity and interfacial thermal conductance play crucial roles in the design of engineering systems where temperature and thermal stress are of concerns. To date, a variety of measurement techniques are available for both bulk and thin film solid-state materials with a broad temperature range. For thermal characterization of bulk material, the steady-state method, transient hot-wire method, laser flash diffusivity method, and transient plane source (TPS) method are most used. For thin film measurement, the 3ω method and the transient thermoreflectance technique including both time-domain and frequency-domain analysis are widely employed. This work reviews several most commonly used measurement techniques. In general, it is a very challenging task to determine thermal conductivity and interfacial thermal conductance with less than 5% error. Selecting a specific measurement technique to characterize thermal properties needs to be based on: (1) knowledge on the sample whose thermophysical properties are to be determined, including the sample geometry and size, and the material preparation method; (2) understanding of fundamentals and procedures of the testing technique, for example, some techniques are limited to samples with specific geometries and some are limited to a specific range of thermophysical properties; and (3) understanding of the potential error sources which might affect the final results, for example, the convection and radiation heat losses.
The Leidenfrost Effect at the Nanoscale
Authors: Cordeiro Jhonatam , Desai Salil
Published: September 2016

Nanotechnology has been presenting successful applications in several fields, such as electronics, medicine, energy, and new materials. However, the high cost of investment in facilities, equipment, and materials as well as the lack of some experimental analysis at the nanoscale can limit research in nanotechnology. The implementation of accurate computer models can alleviate this problem. This research investigates the Leidenfrost effect at the nanoscale using molecular dynamics (MDs) simulation. Models of water droplets with diameters of 4 nm and 10 nm were simulated over gold and silicon substrates. To induce the Leidenfrost effect, droplets at 293 K were deposited on heated substrates at 373 K. As a baseline, simulations were run with substrates at room temperature (293 K). Results show that for substrates at 293 K, the 4 nm droplet has higher position variability than the 10 nm droplets. In addition, for substrates at 373 K, the 4 nm droplets have higher velocities than the 10 nm droplets. The wettability of the substrate also influences the Leidenfrost effect. Droplets over the gold substrate, which has hydrophobic characteristics, have higher velocities as compared to droplets over silicon that has a hydrophilic behavior. Moreover, the Leidenfrost effect was observed at the boiling temperature of water (373 K) which is a significantly lower temperature than reported in previous experiments at the microscale. This research lays the foundation for investigating the fluid–structure interaction within several droplet based micro- and nano-manufacturing processes.
Tip-Based Nanomanufacturing of Nanofluidics Using Atomic Force Microscopy
Authors: Promyoo Rapeepan , El-Mounayri Hazim , Agarwal Mangilal , Karingula Varun Kumar , Varahramyan Kody
Published: September 2016

Presently, nanomanufacturing capabilities limit the commercialization of a broader range of nanoscale structures with higher complexity, greater precision and accuracy, and a substantially improved performance. Atomic force microscopy (AFM)-based nanomachining is a promising technique to address current limitations and is considered a potential manufacturing (MFG) tool for operations such as machining, patterning, and assembling with in situ metrology and visualization. Most existing techniques for fabrication of nanofluidic channels involve the use of electron-beam lithography, which is a very expensive process that requires a lengthy calibration procedure. In this work, atomic force microscopy (AFM) is employed in the fabrication of nanofluidic channels for medical applications. Channels with various depths and widths are fabricated using AFM indentation and scratching. A nanoscale channel is mainly used in the study of the molecular behavior at single molecule level. The resulting device can be used for detecting, analyzing and separating biomolecules, DNA stretching, and separation of elite group of lysosome and other viruses. The nanochannels are integrated between microchannels and act as filters to separate biomolecules. Sharply developed vertical microchannels are produced from deep reaction ion etching. Poly-dimethylsiloxane (PDMS) bonding is performed to close the top surface of the silicon device. An experimental setup is used for testing by flowing fluid through the channels. A cost evaluation shows 47.7% manufacturing-time and 60.6% manufacturing-cost savings, compared to more traditional processes.
Fabrication of a Micro/Nanofluidic Platform Via Three-Axis Robotic Dispensing System
Authors: Yuan Hanwen , Cambron Scott D. , Crain Mark M. , Keynton Robert S.
Published: September 2016

The purpose of this work is to introduce a new fabrication technique for creating a fluidic platform with embedded micro- or nanoscale channels. This new technique includes: (1) a three-axis robotic dispensing system for drawing micro/nanoscale suspended polymer fibers at prescribed locations, combined with (2) dry film resist photolithography, and (3) replica molding. This new technique provides flexibility and precise control of the micro- and nano-channel location with the ability to create multiple channels of varying sizes embedded in a single fluidic platform. These types of micro/nanofluidic platforms are attractive for numerous applications, such as the separation of biomolecules, cell transport, and transport across cell membranes via electroporation. The focus of this work is on the development of a fabrication technique for the creation of a nanoscale electroporation device.
Hydrodynamics of the Interceptor Analysis Via Both Ultrareduced Model Test and Dynamic Computational Fluid Dynamics Simulation
Authors: Mansoori M. , Fernandes A. C.
Published: September 2016

This work investigates the hydrodynamic effects of introducing interceptors on fast vessels. Interceptors are vertical flat blades installed at the bottom of the stern vessel. They cause changes in pressure magnitudes around the vessel bottom and especially at the end of the hull where they are located. The pressure variations have an effect on resistance, draft height, and lifting forces which may result in a better control of trim. This work uses a combination of computational fluid dynamics (CFD) and ultrareduced experimental tests. The investigation applies the Reynolds-averaged Navier–Stokes (RANS) equations to model the flow around the ultrareduced model with interceptors with different heights. Our model is analyzed based on a finite-volume method using dynamic mesh. The boat motion is only with two degrees-of-freedom. The results show that the interceptor causes an intense pressure gradient, decreasing the wet surface of the vessel and, quite surprisingly, the resistance. At last, this paper shows that, within a range, a better trim control is possible. The height of the interceptor has an important effect on interceptor efficiency, and it should be especially selected according to the length of the vessel and boundary layer thickness at the transom. The ultrareduced model tests were performed in the Current Channel of the Laboratory of Waves and Current of COPPE/UFRJ (LOC in Portuguese acronym).
Theoretical and Experimental Analysis of the Steady Flow Across the Cylinderhead of a Low-Capacity Engine
Authors: Castilla A. , Rubio M. , Ferrera C. , Montanero J. M. , Fernández J.
Published: September 2016

The air flow that crosses the cylinderhead of a low-capacity engine is studied both theoretically and experimentally in the steady regime. We analyze the dependence of both the discharge coefficient and swirl number on the Reynolds number and valve lift. The formation of the turbulent vortex in the cylinder is described by measuring the 2D velocity distribution over several cylinder cross sections. The integration of the Reynolds-averaged Navier–Stokes (RANS) equations reproduces satisfactorily the experimental data, especially the swirl number values.
Critical Impact Yaw for Long-Rod Penetrators
Authors: Kong Xiangzhen , Li Q. M. , Fang Qin
Published: September 2016

This paper presents an improved model for the critical impact yaw (or simply the critical yaw) in long-rod penetration with considering the deceleration and rotation of the rod and the crater shape of the target. Two critical yaws, θc1 and θc2, under normal impact were identified, below which there is no contact between the rod and crater sidewall (for θc1) and between the rod and the crater entrance (for θc2) during the entire penetration process. Contact functions and iterative algorithms were proposed in order to obtain these two critical yaws numerically. The influences of four dominant nondimensional numbers (i.e., the ratio of the target resistance to the rod strength λ, Johnson's damage number of the rod ς, square root of the target–projectile density ratio μ, and the diameter–length ratio of the rod ψ) on two critical yaws were studied for three typical rod–target systems (tungsten alloy rods penetrating steel targets, steel rods penetrating aluminum alloy targets, and steel rods penetrating steel targets). The relationship between two critical yaw angles was also discussed. A new empirical formula for the critical yaw θc2 was proposed based on the parametric study results and dominant nondimensional numbers, which extends the valid application range of the existing empirical formula.
Experimental and Numerical Study of a Fixturing System for Complex Geometry and Low Stiffness Components
Authors: Gameros Andrés A. , Axinte Dragos , Siller Héctor R. , Lowth Stewart , Winton Peter
Published: September 2016

The production of freeform components is challenging, not only from the point of view of process optimization but also when it comes to the selection and design of the fixturing systems. Currently, most commercially available fixturing systems are difficult to conform to geometrically complex components; while the systems that manage to provide industrially feasible solutions (such as encapsulation techniques) present several limitations (e.g., high complexity, limited reliability, and risk of elastic deformation of the part). In this context, the present work proposes a simple, yet efficient, concept of a fixture capable of holding complex components through the use of compliant/deformable diaphragm elements. The fundaments of this innovative system (i.e., freeform diaphragm-based fixturing system) have been simulated through an experimentally validated finite-element (FE) model, with results showing a good agreement between numerical and measured data (displacement average error ϵav = 4.04%). The main interactions of the system with a workpiece (e.g., contact area and clamping force) have been numerically and experimentally studied, confirming the system's capacity to generate distributed clamping forces in excess of 1000 N. Based on the modeling activities, an advanced prototype for holding a “generic” freeform component was developed. Using this prototype, a repeatability study then showed the capacity of the system to deterministically position and hold complex geometries. Finally, the proposed fixturing system was thoroughly evaluated under demanding machining conditions (i.e., grinding), and the results showed the ability of the fixture to maintain small part displacement (dx < 10 μm) when high cutting forces are applied (Max. FR = 1021.24 N). Design limitations were observed during the grinding experiments, and the lineaments are presented in order to develop improved further prototypes. Overall, the proposed fixturing approach proved to be a novel and attractive industrial solution for the challenges of locating/holding complex components during manufacture.
Springback Behavior of Carbon-Fiber-Reinforced Plastic Laminates With Metal Cover Layers in V-Die Bending
Authors: Hahn Marlon , Ben Khalifa Nooman , Weddeling Christian , Shabaninejad Arash
Published: September 2016

The V-die bending of a carbon-fiber-reinforced thermoplastic laminate bonded to thin cover layers made of microalloyed steel was investigated. Such hybrid semifinished products are gaining importance in transport-related lightweight designs. Experiments were conducted for different forming temperatures and dwell times to determine suitable process parameters. The punch radius was varied to evaluate its influence on the springback/negative springback of the fiber–metal laminate (FML). The results, which are in good accordance with a simple analytical model, showed that the solidification of the composite core can compensate for the springback of the metal layers. Micrographs further revealed that the fiber orientation can affect the thickness distribution in the bend area.
A Three-Dimensional Time-Accurate Computational Fluid Dynamics Simulation of the Flow Field Inside a Vaneless Diffuser During Rotating Stall Conditions
Authors: Marconcini Michele , Bianchini Alessandro , Checcucci Matteo , Ferrara Giovanni , Arnone Andrea , Ferrari Lorenzo , Biliotti Davide , Rubino Dante Tommaso
Published: September 2016

An accurate characterization of rotating stall in terms of inception modality, flow structures, and stabilizing force is one of the key goals for high-pressure centrifugal compressors. The unbalanced pressure field that is generated within the diffuser can be in fact connected to a non-negligible aerodynamic force and then to the onset of detrimental subsynchronous vibrations, which can prevent the machine from operating beyond this limit. An inner comprehension on how the induced flow pattern in these conditions affects the performance of the impeller and its mechanical stability can therefore lead to the development of a more effective regulation system able to mitigate the effects of the phenomenon and extend the left-side margin of the operating curve. In the present study, a 3D-unsteady computational fluid dynamics (CFD) approach was applied to the simulation of a radial stage model including the impeller, the vaneless diffuser, and the return channel. Simulations were carried out with the TRAF code of the University of Florence. The tested rotor was an industrial impeller operating at high peripheral Mach number, for which unique experimental pressure measurements, including the spatial reconstruction of the pressure field at the diffuser inlet, were available. The comparison between experiments and simulations showed a good matching and corroborated the CFD capabilities in correctly describing also some of the complex unsteady phenomena taking place in proximity of the left margin of the operating curve.
Flexible radioluminescence imaging for FDG‐guided surgery
Authors: King Martin T. , Jenkins Cesare H. , Sun Conroy , Carpenter Colin M. , Ma Xiaowei , Cheng Kai , Le Quynh‐Thu , Sunwoo John B. , Cheng Zhen , Pratx Guillem , Xing Lei
Published: September 2016

Purpose

Flexible radioluminescence imaging (Flex‐RLI) is an optical method for imaging 18F‐fluorodeoxyglucose (FDG)‐avid tumors. The authors hypothesize that a gadolinium oxysulfide: terbium (GOS:Tb) flexible scintillator, which loosely conforms to the body contour, can enhance tumor signal‐to‐background ratio (SBR) compared with RLI, which utilizes a flat scintillator. The purpose of this paper is to characterize flex‐RLI with respect to alternative modalities including RLI, beta‐RLI (RLI with gamma rejection), and Cerenkov luminescence imaging (CLI).

Methods

The photon sensitivity, spatial resolution, and signal linearity of flex‐RLI were characterized with in vitro phantoms. In vivo experiments utilizing 13 nude mice inoculated with the head and neck (UMSCC1‐Luc) cell line were then conducted in accordance with the institutional Administrative Panel on Laboratory Animal Care. After intravenous injection of 18F‐FDG, the tumor SBR values for flex‐RLI were compared to those for RLI, beta‐RLI, and CLI using the Wilcoxon signed rank test.

Results

With respect to photon sensitivity, RLI, beta‐RLI, and flex‐RLI produced 1216.2, 407.0, and 98.6 times more radiance per second than CLI. Respective full‐width half maximum values across a 0.5 mm capillary tube were 6.9, 6.4, 2.2, and 1.5 mm, respectively. Flex‐RLI demonstrated a near perfect correlation with 18F activity (r = 0.99). Signal uniformity for flex‐RLI improved after more aggressive homogenization of the GOS powder with the silicone elastomer during formulation. In vivo, the SBR value for flex‐RLI (median 1.29; interquartile range 1.18–1.36) was statistically greater than that for RLI (1.08; 1.02–1.14; p < 0.01) by 26%. However, there was no statistically significant difference in SBR values between flex‐RLI and beta‐RLI (p = 0.92). Furthermore, there was no statistically significant difference in SBR values between flex‐RLI and CLI (p = 0.11) in a more limited dataset.

Conclusions

Flex‐RLI provides high quality images with SBRs comparable to those from CLI and beta‐RLI in a single 10 s acquisition.
Patient‐specific quantification of image quality: An automated method for measuring spatial resolution in clinical CT images
Authors: Sanders Jeremiah , Hurwitz Lynne , Samei Ehsan
Published: September 2016

Purpose

To develop and validate an automated technique for evaluating the spatial resolution characteristics of clinical computed tomography (CT) images.

Methods

Twenty one chest and abdominopelvic clinical CT datasets were examined in this study. An algorithm was developed to extract a CT resolution index (RI) analogous to the modulation transfer function from clinical CT images by measuring the edge‐spread function (ESF) across the patient's skin. A polygon mesh of the air‐skin boundary was created. The faces of the mesh were then used to measure the ESF across the air‐skin interface. The ESF was differentiated to obtain the line‐spread function (LSF), and the LSF was Fourier transformed to obtain the RI. The algorithm's ability to detect the radial dependence of the RI was investigated. RIs measured with the proposed method were compared with a conventional phantom‐based method across two reconstruction algorithms (FBP and iterative) using the spatial frequency at 50% RI, f50, as the metric for comparison. Three reconstruction kernels were investigated for each reconstruction algorithm. Finally, an observer study was conducted to determine if observers could visually perceive the differences in the measured blurriness of images reconstructed with a given reconstruction method.

Results

RI measurements performed with the proposed technique exhibited the expected dependencies on the image reconstruction. The measured f50 values increased with harder kernels for both FBP and iterative reconstruction. Furthermore, the proposed algorithm was able to detect the radial dependence of the RI. Patient‐specific measurements of the RI were comparable to the phantom‐based technique, but the patient data exhibited a large spread in the measured f50, indicating that some datasets were blurrier than others even when the projection data were reconstructed with the same reconstruction algorithm and kernel. Results from the observer study substantiated this finding.

Conclusions

Clinically informed, patient‐specific spatial resolution can be measured from clinical datasets. The method is sufficiently sensitive to reflect changes in spatial resolution due to different reconstruction parameters. The method can be applied to automatically assess the spatial resolution of patient images and quantify dependencies that may not be captured in phantom data.
Sagittal Plane Gait Kinematics in Individuals With Chronic Ankle Instability
Authors: Hoch Matthew C. , Mullineaux David R. , Jeon Kyoungkyu , McKeon Patrick O.
Published: September 2016

Single joint kinematic alterations have been identified during gait in those with chronic ankle instability (CAI). The purpose of this study was to compare sagittal plane hip, knee, and ankle kinematics during walking in participants with and without CAI. Twelve individuals with CAI and 12 healthy individuals walked on a treadmill at 1.5 m/s. Three-dimensional kinematics were analyzed using mean ensemble curves and independent t tests. Participants with CAI demonstrated less lower extremity flexion during the absorption phase of stance and the limb placement phase of swing, which may have implications for limb placement at initial contact.
Neurologic Thoracic Outlet Syndrome: A Case Report and Clinical Review
Authors: Billy Gregory G. , Miller Sayers J.
Published: September 2016

An avid weightlifter presented with complaints of right arm and hand numbness. His workup was consistent with neurologic thoracic outlet syndrome with severe conduction block at the level of the supraclavicular fossa. He chose conservative treatment, which focused on correction of thoracic and cervical segmental dysfunction, upper crossed syndrome muscle imbalances, and upper trunk and anterior forward head postural concerns. Upon completion of the therapy program and continuation of a home exercise program, his conduction block and symptoms resolved. Conservative treatment may be an effective alternative to surgery for neurologic thoracic outlet syndrome.
Novel Treatment of Apparent Posterior Ankle Impingement Syndrome Related to a StiedaProcess Utilizing the Mulligan Concept: An Exploration Case Study
Authors: Rhinehart Alex J. , Guindon Caroline C.
Published: September 2016

A 21-year-old female NCAA Division III soccer player presented with an insidious onset of posterior ankle pain. Lateral radiographs revealed a Stieda process, leading to a physician diagnosis of posterior ankle impingement (PAI). Mulligan Concept mobilizations with movement (MWM) were used to ameliorate patient complaints. The MWM glide was maintained during activity using a tape application. Return to play and patient improvement occurred dramatically faster while utilizing the MWM technique than other traditional methods used to treat this condition. This case report demonstrates a novel approach to treating Stieda process-related PAI that warrants further clinical inquiry.
The Effectiveness of Posterior Shoulder Stretching on Reducing Posterior Shoulder Tightness in Overhead Athletes: A Critically Appraised Topic
Authors: Pathoomvanh Megan , Feldbrugge Chase , Welsch Lauren , Van Lunen Bonnie
Published: September 2016

Clinical Question:

Are posterior shoulder stretching programs effective in reducing posterior shoulder tightness, or tightness to the soft tissue of the shoulder, in overhead athletes?

Clinical Bottom Line:

In overhead athletes, there is high quality evidence to support the use of posterior shoulder stretching to reduce a commonly used measure of posterior shoulder tightness. All three studies1–3 reported an increase in shoulder internal rotation range of motion following implementation of posterior shoulder stretching.
Effects of Ultratrail Running on Skeletal-Muscle Oxygenation Dynamics
Authors: Vernillo Gianluca , Brighenti Alfredo , Limonta Eloisa , Trabucchi Pietro , Malatesta Davide , Millet Grégoire P. , Schena Federico
Published: September 2016

Purpose:

To quantify changes in skeletal-muscle oxygenation and pulmonary O2 uptake (V̇O2) after an extreme ultratrail running bout.

Methods:

Before (PRE) and after (POST) the race (330-km, 24000 D±), profiles of vastus lateralis muscle oxygenation (ie, oxyhemoglobin [O2Hb], deoxyhemoglobin [HHb], and tissue oxygenation index [TOI]) and V̇O2 were determined in 14 athletes (EXP) and 12 control adults (CON) during two 4-min constant-load cycling bouts at power outputs of 1 (p1) and 1.5 (p1.5) W/kg performed in randomized order.

Results:

At POST, normalized [HHb] values increased (p1, +38.0%; p1.5, +27.9%; P < .05), while normalized [O2Hb] (p1, –20.4%; p1.5, –14.4%; P < .05) and TOI (p1, –17.0%; p1.5, –17.7%; P < .05) decreased in EXP. V̇O2 values were similar (P > 0.05). An “overshoot“ in normalized [HHb]:V̇O2 was observed, although the increase was significant only during p1.5 (+58.7%, P = .003). No difference in the aforementioned variables was noted in CON (P > .05).

Conclusions:

The concentric and, particularly, the eccentric loads characterizing this extreme ultratrail-running bout may have led to variations in muscle structure and function, increasing the local muscle deoxygenation profile and the imbalance between O2 delivery to working muscles and muscle O2 consumption. This highlights the importance of incorporating graded training, particularly downhill bouts, to reduce the negative influence of concentric and severe eccentric loads to the microcirculatory function and to enhance the ability of runners to sustain such loading.
Similar Running Economy With Different Running Patterns Along the Aerial-Terrestrial Continuum
Authors: Lussiana Thibault , Gindre Cyrille , Hébert-Losier Kim , Sagawa Yoshimasa , Gimenez Philippe , Mourot Laurent
Published: September 2016

Purpose:

No unique or ideal running pattern is the most economical for all runners. Classifying the global running patterns of individuals into 2 categories (aerial and terrestrial) using the Volodalen method could permit a better understanding of the relationship between running economy (RE) and biomechanics. The main purpose was to compare the RE of aerial and terrestrial runners.

Methods:

Two coaches classified 58 runners into aerial (n = 29) or terrestrial (n = 29) running patterns on the basis of visual observations. RE, muscle activity, kinematics, and spatiotemporal parameters of both groups were measured during a 5-min run at 12 km/h on a treadmill. Maximal oxygen uptake (V̇O2max) and peak treadmill speed (PTS) were assessed during an incremental running test.

Results:

No differences were observed between aerial and terrestrial patterns for RE, V̇O2max, and PTS. However, at 12 km/h, aerial runners exhibited earlier gastrocnemius lateralis activation in preparation for contact, less dorsiflexion at ground contact, higher coactivation indexes, and greater leg stiffness during stance phase than terrestrial runners. Terrestrial runners had more pronounced semitendinosus activation at the start and end of the running cycle, shorter flight time, greater leg compression, and a more rear-foot strike.

Conclusions:

Different running patterns were associated with similar RE. Aerial runners appear to rely more on elastic energy utilization with a rapid eccentric-concentric coupling time, whereas terrestrial runners appear to propel the body more forward rather than upward to limit work against gravity. Excluding runners with a mixed running pattern from analyses did not affect study interpretation.
Effect of Tibia Marker Placement on Kinematics in Pathological Gait
Authors: Nazareth Alexander , Mueske Nicole M. , Wren Tishya A.L.
Published: September 2016

This study aimed to determine the effect of tibia marker placement on walking kinematics in children with pathological gait. Three-dimensional lower extremity gait data were collected using both a traditional tibia wand (protruding laterally from the distal shank) and a tibia crest marker on 25 children with pathological gait. Kinematic variables during walking and quiet standing were calculated using each marker and the “Plug-in Gait” implementation of the conventional gait model. For walking, average differences in kinematics between tibia markers ranged from 0.1° to 1.9° at the knee and ankle, except in the transverse plane where differences were 6.0° to 7.2°. No significant differences were found during quiet standing, indicating that differences in kinematics derive primarily from dynamic sources, which likely affect the tibia wand more than the tibia crest marker. These results suggest that the tibia crest marker can be used in place of the traditional tibia wand in clinical gait analysis.
The Effect of Magnesium Carbonate (Chalk) on Geometric Entropy, Force, and Electromyography During Rock Climbing
Authors: Kilgas Matthew A. , Drum Scott N. , Jensen Randall L. , Phillips Kevin C. , Watts Phillip B.
Published: September 2016

Rock climbers believe chalk dries the hands of sweat and improves the static coefficient of friction between the hands and the surface of the rock. The purpose of this study was to assess whether chalk affects geometric entropy or muscular activity during rock climbing. Nineteen experienced recreational rock climbers (13 males, 6 females; 173.5 ± 7.0 cm; 67.5 ± 3.4 kg) completed 2 climbing trails with and without chalk. The body position of the climber and muscular activity of the finger flexors was recorded throughout the trial. Following the movement sequence participants hung from a standard climbing hold until they slipped from the climbing structure, while the coefficient of friction and the ratio of the vertical forces on the hands and feet were determined. Although there were no differences in the coefficient of friction (P = .748), geometric entropy (P = .359), the ratio of the vertical forces between the hands and feet (P = .570), or muscular activity (P = .968), participants were able to hang longer after the use of chalk 62.9 ± 36.7 s and 49.3 ± 25.2 s (P = .046). This is advantageous because it may allow for prolonged rests, and more time to plan the next series of climbing moves.
Combined Ankle–Foot Energetics are Conserved When Distal Foot Energy Absorption is Minimized
Authors: Arch Elisa S. , Fylstra Bretta L.
Published: September 2016

The large, late-stance energy generated by the ankle is believed to be critical during gait. However, the distal foot absorbs/dissipates a considerable amount of energy during the same phase. Thus, the energy generated by the combined ankle–foot system is more modest, which raises questions regarding the necessity of such a large ankle power and the interplay between foot and ankle energetics. This study aimed to evaluate our conservation of energy hypothesis, which predicted if distal foot energy absorption/dissipation was reduced, then less energy would be generated at the ankle and thus the same combined ankle–foot energetics would be achieved. Motion analysis data were collected as healthy subjects walked under 2 conditions (Shoes, Footplate). In the Footplate condition, the shoe was replaced with a customized, rigid footplate with a rocker profile. In support of the hypothesis, there was significantly less positive ankle and less negative distal foot work with footplate use, resulting in very similar combined ankle–foot work between conditions. These findings suggest that there is an interplay between the energy generated by the ankle and absorbed by the foot. This interplay should be considered when designing orthotic and prosthetic ankle–foot systems and rehabilitation programs for individuals with weakened ankle muscles.
Relationships of Muscle Echo Intensity with Walking Ability and Physical Activity in the Very Old Population
Authors: Osawa Yusuke , Arai Yasumichi , Oguma Yuko , Hirata Takumi , Abe Yukiko , Azuma Koichiro , Takayama Michiyo , Hirose Nobuyoshi
Published: September 2016

This study investigated the relationships between muscle echo intensity (EI), physical activity (PA), and functional mobility in 108 Japanese (88–92 years). We measured EI and muscle thickness (MT) at the midpoint of the anterior superior iliac spine and patella using B-mode ultrasound. Light and moderate-to-vigorous PA (LPA and MVPA) were assessed with a triaxial accelerometer. The timed up and go (TUG) test was used to measure for functional mobility. EI, but not MT, was significantly associated with both TUG scores (β = 0.17, p = .047) and MVPA (β = –0.31, p = .01) when adjusted by potential confounders. However, association between EI and TUG disappeared after adjusted for MVPA. Meanwhile, MVPA was significantly associated with TUG scores independent of EI (β = –0.35, p < .001). Although EI of anterior thigh muscles might be a weaker predictor of functional morbidity than MVPA, it is a noninvasive and practical approach for assessing muscle quality in the very old.
Joint Association of Neighborhood Environment and Fear of Falling on Physical Activity Among Frail Older Adults
Authors: Harada Kazuhiro , Park Hyuntae , Lee Sangyoon , Shimada Hiroyuki , Yoshida Daisuke , Anan Yuya , Suzuki Takao
Published: September 2016

This study examined associations between perceived neighborhood environment and physical activity among frail older adults and whether these associations are moderated by fear of falling. Participants were 238 frail older adults. Daily step counts and duration of moderate-to-vigorous physical activity were measured using an accelerometer. Participants completed the abbreviated Neighborhood Environment Walkability Scale; fear of falling and demographic and health-related factors were measured by a questionnaire. The interaction between crime safety and fear of falling was significantly associated with step count (p = .009) and moderate-to-vigorous physical activity (p = .018) in multiple regression analysis. Stratified according to fear of falling, crime safety was significantly associated with steps (p = .007) and moderate-to-vigorous physical activity (p = .030) in the low fear of falling group. The results suggest that crime safety is associated with physical activity among frail older adults, and this association is moderated by fear of falling.
The Influence of Pay-To-Play Fees on Participation in Interscholastic Sports: A School-Level Analysis of Michigan’s Public Schools
Authors: Zdroik Jennifer , Veliz Philip
Published: September 2016

Background:

School districts in the United States are turning toward new sources of revenue to maintain their interscholastic sports programs. One common revenue generating policy is the implementation of participation fees, also known as pay-to-play. One concern of the growing trend of participation fees is how it impacts student participation opportunities. This study looks at how pay-to-play fees are impacting participation opportunities and participation rates in the state of Michigan.

Methods:

Through merging 3 school-level data sets, Civil Rights Data Collection, the Common Core of Data, and participation information from MHSAA (Michigan High School Athletic Association), bivariate analysis and ordinary least squares regression were used in our analysis.

Results:

Our findings indicate that certain types of schools are able to support pay-to-play fees: relatively large schools that are located in suburban, white communities, with relatively low poverty rates. We also found that participation fees are not decreasing the number of sport opportunities for students, participation opportunities are higher in schools with fees; but participation rates are similar between schools with and without participation fees.

Conclusions:

Participation fee policy implications are discussed and we offer suggestions for future research.
Physical Activity in an Underserved Population: Identifying Technology Preferences
Authors: Medairos Robert , Kang Vicky , Aboubakare Carissa , Kramer Matthew , Dugan Sheila Ann
Published: September 2016

Background:

This study aims to identify patterns of use and preferences related to technology platforms that could support physical activity (PA) programs in an underserved population.

Methods:

A 29-item questionnaire was administered at 5 health and wellness sites targeting low income communities in Chicago. Frequency tables were generated for Internet, cell phone, and social media use and preferences. Chi-squared analysis was used to evaluate differences across age and income groups.

Results:

A total of 291 individuals participated and were predominantly female (69.0%). Majority reported incomes less than $30,000 (72.9%) and identified as African American/Black/Caribbean (49.3%) or Mexican/Mexican American (34.3%). Most participants regularly used smartphones (63.2%) and the Internet (75.9%). Respondents frequently used Facebook (84.8%), and less commonly used Instagram (43.6%), and Twitter (20.0%). Free Internet-based exercise programs were the most preferred method to increase PA levels (31.6%), while some respondents (21.0%) thought none of the surveyed technology applications would help.

Conclusion:

Cell phone, Internet, and social media use is common among the surveyed underserved population. Technology preferences to increase PA levels varied, with a considerable number of respondents not preferring the surveyed technology platforms. Creating educational opportunities to increase awareness may maximize the effectiveness of technology-based PA interventions.
“What it Means to be a ‘Lady’”: Defending the “Lady Vols” Nickname and Logo
Authors: Dzikus Lars , Smith Allison B. , Evans Jonathan
Published: September 2016

Scholars have contested the use of Lady in team nicknames since the 1980s, as the practice might suggest otherness and inferiority (Eitzen & Zinn, 1989). This study is set in the context of the 2012 merger of the women’s athletic departments at the University of Tennessee and the 2014 announcement that the university would eliminate the Lady Vols brand for all sports but women’s basketball. The latter decision has been met with resistance and applause from various parties. Using textual analysis of voices of athletes and comparing and contrasting them with perspectives of scholars, this study suggests a reading of Lady and Lady Vols as polysemic text with coexisting and competing cultural interpretations.

Les universitaires ont contesté l’utilisation du terme Lady dans les surnoms des équipes dès les années 80, étant donné que cette pratique pouvait suggérer l’altérité et l’infériorité (Eitzen & Zinn, 1989). Cette étude s’inscrit dans le contexte de la fusion des départements sportifs de l’Université du Tennessee en 2012 et de l’annonce faite en 2014 que l’université supprimerait la marque Lady Vols, hormis pour le basket féminin. Cette décision a rencontré des résistances et des applaudissements de la part de différentes parties. En se basant sur une analyse textuelle des positions prises par des athlètes et en les comparant et les contrastant avec les perspectives d’universitaires, cette étude suggère une lecture des termes Lady et Lady Vols comme un texte polysémique avec la coexistence d’interprétations culturelles concurrentes.
Professional Tennis on the ATP Tour: A Case Study of Mental Skills Support
Authors: Mathers John F.
Published: September 2016

Success on the Association of Tennis Professionals (ATP) World Tour requires a specific blend of perceptuomotor abilities, technical proficiency, tactical awareness and mental skills. This case study describes the competitive structure of professional tennis and outlines the program of mental skills delivered to a professional tennis player over a 3-year period. The program embraced five stages: (1) education; (2) assessment/profiling; (3) mental skill learning; (4) application of mental skills in context and (5) evaluation, and was associated with some positive outcomes. This case study provides some possible guidelines for sport psychologists who may wish to provide consultancy services within professional tennis.
The atmosphere's pacemaker skips a beat
Authors: Mason Betsy
Published: September 2016

Hiccup bodes wet winter weather for Europe.
No proof that predator culls save livestock, study claims
Authors: Goldfarb Ben
Published: September 2016

New analysis calls for more rigorous studies.
Forgotten but not lost
Authors: Ferrarelli Leslie K.
Published: September 2016

The ability to recall events from only about age 4 is the result of an NMDAR subunit switch–mediated maturation of the hippocampus.
Eosinophilic ascites: a diagnostic challenge
Authors: Khalil Hesham , Joseph Moby
Published: September 2016

Eosinophilic ascites is a rare feature of eosinophilic gastroenteritis. We would like to highlight this increasingly recognised diagnosis in a case of unexplained ascites. We present a challenging case of a woman aged 25 years who presented with nausea, vomiting, diarrhoea, generalised abdominal pain and swelling 8-week following delivery of her first baby. Her symptoms were primarily aggravated by eating, and she had also noticed postprandial itching and self-limiting generalised rash. She had a strong history of atopy. Physical examination revealed abdominal tenderness and distension with shifting dullness. Urticarial skin rash was noted on the face, neck, chest and abdomen. Routine biochemistry was normal apart from peripheral eosinophilia. Imaging confirmed moderate ascites. Diagnostic paracentesis showed exudative ascites with numerous eosinophils. Histology of the upper and lower gastrointestinal tract showed infiltration of the oesophageogastroduodenal and rectosigmoid mucosa with eosinophils. The patient significantly improved following a course of steroids and six-food elimination diet.
The role of multidisciplinary meetings for benign pancreatobiliary diseases: a tertiary centre experience
Authors: Bekkali Noor L H , Murray Sam , Winter Lesley , Sehgal Vinay , Webster George J M , Chapman Michael H , Bandula Steven , Amin Zahir , Read Samantha , Pereira Stephen P , Johnson Gavin J
Published: September 2016

Multidisciplinary meetings are central to the management of chronic and complex diseases and they have become widely established across the modern healthcare. Patients with pancreatobiliary diseases can often present with complex clinical dilemmas, which fall out with the scope of current guidelines. Therefore, these patients require a personalised management approach discussed in a multidisciplinary meeting.
Selection bias in follow-up interviews with individuals attending the emergency department for occupational injuries
Authors: Oesterlund Anna H , Lander Flemming , Rytter Søren , Lauritsen Jens
Published: September 2016

Objective

To examine whether supplementary interview participation was comparable for occupationally injured patients attending two hospital emergency departments and to investigate the magnitude of selection bias in relation to sex, age, severity, job tasks and industry risk level.

Methods

Workers aged 18–70 years who contacted the two emergency departments for an acute occupational injury in 2013 were eligible and given a short questionnaire. Following written consent, a semi-structured interview concerning health and transient risk factors was conducted by telephone. The two departments were compared for study recruitment by age and sex. Respondents and non-respondents to the interview were compared for age, sex, injury severity, job tasks and industry risk level.

Results

Of 4002 patients attending the two hospitals, 1693 (42%) participated in the interview. One hospital had a markedly higher response rate to the questionnaire, but the proportions of participation in the interview were similar in the two hospitals. Patients aged <30 years were over-represented among non-respondents whereas sex, injury severity, job task and industry risk level were not significantly different between respondents and non-respondents.

Conclusions

Despite a relatively low interview participation rate among injured individuals attending the emergency department, selection bias was limited. This indicates that results regarding injury risk patterns may be more widely generalisable when examining the causality of occupational injuries. However, the study also showed that young injured workers were less likely to participate in follow-up interviews, which is an important factor when interpreting age-related risk of injury.
Development and validation of a new ICD-10-based trauma mortality prediction scoring system using a Japanese national inpatient database
Authors: Wada Tomoki , Yasunaga Hideo , Yamana Hayato , Matsui Hiroki , Matsubara Takehiro , Fushimi Kiyohide , Nakajima Susumu
Published: September 2016

Introduction

To develop and validate a new trauma mortality prediction scoring system based on International Statistical Classification of Diseases (ICD)-10 codes, using a Japanese administrative claims and discharge abstract database.

Methods

This retrospective observational study used the Japanese Diagnosis Procedure Combination database. Injuries were categorised into 33 groups with 5 additional groups based on injury sites and types. A multivariable logistic regression analysis was performed for in-hospital mortality in a derivation cohort after adjusting for the 38 groups, patient's sex, age and Charlson Comorbidity Index score. Each variable was assigned a score that was equal to the value of the regression coefficient. The new severity score was defined as the sum of the scores. The new scoring system was tested in a validation cohort.

Results

The mortality rates were 2.4% (9270/393 395) and 2.5% (8778/349 285) in the derivation and validation cohorts, respectively. The area under the receiver operating curve (AUROC) of the new scoring system was 0.887 (95% CI 0.884 to 0.890) in the validation cohort. Subgroup analyses showed that the scoring system retained high predictive performance both for patients <65 years (AUROC 0.934, 95% CI 0.928 to 0.939) and for elderly patients at the age of ≥65 years (AUROC 0.825, 95% CI 0.820 to 0.829).

Conclusions

A new ICD-10-based injury severity scoring system was developed and validated. Further studies are required to validate the scoring system in other databases.
Singularity-free interaction in dilaton-Maxwell electrodynamics
Authors: Kechkin O. V. , Mosharev P. A.
Published: September 2016

An effective potential is created for the dynamics of a test particle, which preserves dilatation symmetry for nonlinear static dilaton-Maxwell background. It is found that the central interaction in this theory is singularity-free everywhere; it vanishes at short distances and demonstrates Coulomb behavior far from the source. It is shown that static and spherically symmetric source behaves like a soliton: it has the finite energy characteristics that are inversely proportional to the dilaton-Maxwell coupling constant.