bluuebunny/crossref_metadata_2025 huggingface dataset:
LM2500 Reliability Improvements for United States Navy Applications
Authors: Driscoll Matthew , Habib Thomas , Arseneau William
Published: August 2014

The United States Navy uses the General Electric LM2500 gas turbine engine for main propulsion on its newest surface combatants including the OLIVER HAZARD PERRY (FFG 7) class frigates, SPRUANCE (DD 963) class destroyers, TICONDEROGA (CG 47) class cruisers, ARLIEGH BURKE (DDG 51) class destroyers and SUPPLY (AOE 6) class oilers. Currently, the Navy operates a fleet of over 400 LM2500 gas turbine engines. This paper discusses the ongoing efforts to characterize the availability of the engines aboard ship and pinpoint systems/components that have significant impact on engine reliability. In addition, the program plan to upgrade the LM2500’s standard configuration to improve reliability is delineated.
WR21 Intercooled Recuperated (ICR) Gas Turbine Engine System Level Development Test Program Summary
Authors: Janton Jay T. , Uawithya Chai
Published: August 2014

The WR21 Intercooled Recuperated (ICR) Gas Turbine engine has undergone system level development testing from July of 1994 to December 1999. There have been a total of ten engine builds and 2126 hours of engine operation performed through December of 1999. A significant number of unique development tests (experiments) have been performed over the ten engine builds. The last development test just completed and that was a USN specified 500-hour endurance test from 4 October through 16 December of 1999.

All the development testing to date has been performed at the Defense Evaluation and Research Agency (DERA), Pyestock, England which is part of the UK Ministry of Defense (MOD). The last 500-hour endurance test was performed at the Advanced Propulsion & Power Generation Test Site (APPGTS) located at the Naval Surface Warfare Center Carderock Division (NSWCCD), Philadelphia, PA. The system level testing performed has evaluated the gas generator, power turbine, enclosure systems, recuperator, intercooler, and engine electronic controller (EEC). The enclosure systems include two off-engine skids (lube oil module and Intercooler Heat Exchanger module), accessory gearbox, fire protection system, enclosure cooling system, water wash, structureborne and airborne noise, fuel system and air start system.

A three-phase development test strategy was employed. The first phase was to demonstrate the ICR technology and identify the highest-risk areas. Due to the unique challenges introduced by the intercooler, recuperator, variable area nozzles, and new EEC the test program was continually reviewed and revised. The second phase focused on component and system improvements. The final phase is the verification of the ICR in a 500-hr endurance test. At the completion of development testing a final design review will be held (DR5), followed by qualification testing. The qualification tests will include a 3150-hr endurance test and shock test. This paper summarizes and discusses the major tests performed during the development phases. The plan for the final development 500-hr endurance test and 3150-hr qualification test will be presented.
Life Extending Advanced Component Repairs — Field Operating Experience
Authors: Cooke Lloyd A.
Published: August 2014

Advanced repair technologies have been introduced to the gas turbine industry over recent years. An increasing selection of coating systems is available which can be tailored to the specific operating environment. Automated welding systems and the use of custom weld filler metals for enhanced component life provide a means of reliably welding the new generation of high strength turbine blade alloys. Powder metallurgy processes have been introduced as an alternative to welding and have been used to upgrade certain components by employing higher strength repair materials than the original castings.

In the paper, these and other technologies are assessed based on engine operating experience with direct comparison to the conventional repair techniques which they have replaced.
Improved Vibration Monitoring Through Optimization of Sensor Placements
Authors: Sensmeier Mark D. , Nichol Kurt L.
Published: August 2014

A PC-based software tool has been developed which optimizes the placement of sensors for vibration monitoring. This tool, called Blade-OPS, incorporates a methodology that allows the instrumentation design engineer to make tradeoffs between mode identification, mode visibility, data integrity and geometry. It uses a genetic algorithm optimization approach that simulates the natural selection process to develop an optimum design. For the blade considered here, several instrumentation configurations were selected which yield an improved fitness rating relative to the baseline sensor locations which were selected without using rigorous optimization approach. Application of this capability is not limited to turbine engine components, but will be useful for any dynamic test where instrumentation is limited.
25-5 Kwe Microturbine Design Aspects
Authors: Rodgers C.
Published: August 2014

In concert with the growing emphasis placed on distributed power generation there will be a need, in the first decade of the 21st century, for a compact thermal energy system capable of providing the total energy needs of individual homes. A natural gas fueled cogeneration microturbine with ultra low emissions will meet this need.

The results of a study to assess the thermal and economic aspects of microturbines in the 25 to 5 Kwe range are presented. It was determined that with current state of art component peak performance levels, and metallic materials, thermal efficiency goals of 27 and 22.5% respectively at sea level standard day conditions are attainable. Higher overall thermal efficiencies of 60% are attainable with a microturbine combined with a fuel cell, and approaching 80% combined with exhaust fired boilers.

Development of a low cost natural gas combustor injection method, combined with a low cost high effectiveness recuperator were considered mandatory for market acceptance.
An Advanced Model Based Health Monitoring System to Reduce Gas Turbine Ownership Cost
Authors: Razak A. M. Y. , Carlyle J. S.
Published: August 2014

The health of gas turbines is vital for profitability. All gas turbines deteriorate in performance during operation resulting in reduce revenue and increasing costs. The paper discusses the application of gas turbine models to detect damage at engine component level. The method also enables the detection of instrument faults. An example of this method has been applied to an aero derived gas turbine. The impact of performance deterioration on engine life is also discussed. The paper also discusses a method to highlight combustion problems and thereby prevent major failures of the hot end components. The paper concludes by using the fault detection method and creep life analysis to develop a suitable strategy for a predictive based maintenance system.
Three-Dimensional Investigations for Axial Turbines by an Implicit Unstructured Multi-Block Flow Solver
Authors: Adami P. , Martelli F. , Michelassi V.
Published: August 2014

An unstructured 3D implicit approach (HybFlow) is briefly described for gas turbine applications. The numerical approach is based in an upwind finite volume scheme with an implicit time marching algorithm. The linear solver is GMRES with right preconditioning obtained by the ILU(0) incomplete factorization. A two k-w turbulence model is considered for viscous flows. The new multiblock extension of the code is here considered for improving the computational efficiency of the basic procedure in view of the application to complex 3D geometries. Particular concern has been placed in the new approach for memory saving while keeping at the same time a great geometrical flexibility and grid transparency. The strategy developed is therefore described considering the whole process and all phases required in the solution of internal flows.

Both memory and CPU time costs are addressed to verify the performances of the multiblock scheme as also computational accuracy for 2D tests. The flow conditions investigated range from the low speed regime up to the transonic one to prove the accuracy of the approach using hybrid unstructured configurations. Finally the application to the transonic cooled annular IGV blade row is considered to assess the multiblock strategy for a 3D case.
Control System Design for Active Lubrication With Theoretical and Experimental Examples
Authors: Santos Ilmar F. , Scalabrin Alexandre
Published: August 2014

This work focuses on the theoretical and experimental behavior of rigid rotors controlled by tilting-pad journal bearings with active oil injection. Initially the mathematical model of the active bearing is presented: the equations that describe the dynamics of hydraulic actuators are introduced into the equations of the lubricant, resulting in a new form of Reynolds’ equation for active lubrication. The global model of the system is obtained by coupling the equation of motion of the rigid rotor with the stiffness and damping of the active oil film. This global model is then used to design the control system of the active bearing based on root locus curves. The active system stability is analyzed by calculating its eigen values and frequency response curves. The theoretical and experimental results show that this kind of bearing can significantly reduce the vibration level of rotating machinery.
Refined Stochastic Field Models for Jet Engine Vibration and Fault Diagnostics
Authors: Ghiocel Dan M.
Published: August 2014

The paper proposes a refined stochastic fault classifier for jet engine vibration diagnostic based on advanced stochastic concepts. The statistical data to be analyzed are the spectrum profiles of vibration measured at different locations in the engine. The statistical spectrum profiles are idealized by non-homogeneous stochastic fields with non-Gaussian probability distributions. The proposed stochastic classifier is based on the decomposition of the statistical correlation matrix of spectrum profiles using a Karhunen-Loeve (KL) expansion. Two stochastic classifiers are proposed, namely a “global” and a “specific” fault classifier. The “global” KL classifier, which is a scalar quantity, is an efficient anomaly/novelty detection tool for identifying incipient fault diagnosis with small amplitude fluctuations. The “specific” KL classifier, which is a vector quantity, is a refined diagnostic tool for identifying the engine malfunction causes. An illustrative example of a turbofan engine is included.
Research and Development of Practical Industrial Cogeneration Technology in Japan
Authors: Abe Toshiaki , Sugiura Takashi , Okunaga Shuji , Nojima Katsuhiro , Tsutsui Yasukata , Matsunuma Takayuki
Published: August 2014

This paper presents an overview of a development project involving industrial cogeneration technology using 8,000-kW class hybrid gas turbines in which both metal and ceramics are used in parts subject to high temperatures in order to achieve high efficiency and low pollution.

The development of hybrid gas turbines focuses mainly on the earlier commercialization of the turbine system. Stationary parts such as combustor liners, transition ducts, and first-stage turbine nozzles (stationary blades) are expected to be fabricated from ceramics. The project aims at developing material for these ceramic parts that will have a superior resistance to heat and oxidation. The project also aims at designing and prototyping a hybrid gas turbine system to analyze the operation in order to improve the performance. Furthermore, the prototyped hybrid gas turbine system will be tested for long-term operation (4,000 hours) to verify that the system can withstand commercialization. Studies will be conducted to ensure that the system’s soundness and reliability are sufficient for industrial cogeneration applications.
In-Duct Measurement of Gas Turbine Noise Emmisions Using a Cross Spectrum Method
Authors: Sacks M. P. , Kawall J. G. , Behboudi R. , Buttell J.
Published: August 2014

It is often desirable to measure the sound power radiated by the inlet or exhaust of a gas turbine in an installation that includes filters and silencers. A direct measurement can only be accomplished within the empty duct between the inlet or exhaust flange and the silencer. For a number of reasons ISO 5136 [1] cannot be used directly to perform these measurements. Consequently, some other means must be found.

The primary requirement for an in-duct sound power measurement is a valid in-duct sound pressure measurement. In order to accomplish this, the effect of the turbulent pressure fluctuations inherent in the flow, or induced by the microphone probes, must be removed from the dynamic pressure signals sensed by the microphone.

This paper describes the use of a two-microphone cross amplitude spectrum (CAS) technique to perform accurate measurements of the autospectra of sound fields embedded in turbulent duct flows. This technique is based on the assumption that the acoustic and turbulence signals detected by any microphone are uncorrelated with each other and also with the turbulence signals detected by another microphone.

The paper gives the measurement parameters required for various degrees of turbulence rejection as well as the accuracy and convergence of the estimate of the embedded acoustic spectrum. The paper also provides a means to determine the microphone separation distance required to ensure that the turbulence signals at the two microphones are uncorrelated. These results are based on both the simulation of acoustic fields embedded in turbulence and on laboratory experiments using both loudspeakers and an aeroacoustic wind tunnel.

Typical results show that for practical measurement durations the proposed method will provide a turbulence rejection in octave bands of approximately 15 dB at 31.5 Hz rising smoothly to 25 dB at 8 kHz. The method thus appears to have some distinct advantages over ISO 5136 methodology.
Degradation of Silicon Nitrides in High Pressure, Moisture Rich Environments
Authors: Ferber M. K. , Lin H. T. , Parthasarathy V. , Wenglarz R. A.
Published: August 2014

This paper provides a review of a recent study undertaken to examine the mechanical and thermal stability of silicon nitride ceramic nozzles exposed in an industrial gas turbine. The average temperature and pressure of gas entering the vanes were approximately 1066°C and 8.9 atm, respectively. The total exposure time was 815 h including a 22 h shakedown test. Scanning electron microscopy was used to elucidate the changes in the microstructures arising from the oxidation process. The recession of the airfoils arising from the volatilization of the normally protective silica layer was also measured. The stability of the intergranular phases was evaluated using x-ray diffraction. The surface strength was measured using a miniature biaxial test specimen which was prepared by diamond core drilling.
Degradation of Silicon Carbide in Combustion Gas Flow at High-Temperature and Speed
Authors: Yuri I. , Hisamatsu T. , Etori Y. , Yamamoto T.
Published: August 2014

Effects of various basic factors of combustion gas flow conditions on degradation behaviors of silicon carbide have been experimentally determined. The exposure tests were performed for widely varied experimental parameters of the gas temperatures (T = 900–1500°C), pressure (P = 0.3–0.8MPa), gas flow rate (V = 50–250m/s), water vapor partial pressure (PH2O = 32–82kPa) and oxygen partial pressure (PO2 = 24–44kPa). Degradation behaviors of silicon carbide were expressed as the weight loss of the substrate. The weight loss rate depends on the water vapor partial pressure remarkably. The effect of the oxygen partial pressure on the weight loss was smaller than that of the water vapor partial pressure, and the weight loss decreased with the increase of the oxygen partial pressure. Considering the effects of partial pressures of oxygen and water vapor, the gas temperature and the pressure didn’t have much effect on the weight loss. The weight loss depends on the gas flow rate, the increase rate of the weight loss for the gas flow rate becomes small with the gas flow rate. Consequently, the water vapor partial pressure, the oxygen partial pressure, the gas temperature, the pressure and the gas flow rate dependence of the weight loss rate is expressed as PH2O1.9 V0.6 P0.3 / PO20.6.
Doped semiconductors with band-edge plasma frequencies
Authors: Law Stephanie , Liu Runyu , Wasserman Daniel
Published: August 2014

In this work, the authors demonstrate the potential of epitaxially grown highly doped InSb as an engineered, wavelength-flexible mid-IR plasmonic material. The authors achieve doping concentrations over an order of magnitude larger than previously published results and show that such materials have plasma frequencies corresponding to energies larger than the material's band-gap. These semiconductor-based plasmonic metals open the door to homoepitaxial integration of plasmonic or epsilon-near-zero materials with optoelectronic devices at mid-infrared wavelengths. The materials are characterized by Hall measurements, mid-infrared transmission and reflection spectroscopy, and near-infrared transmission spectroscopy. The opportunities offered and the limitations presented by this material system are discussed and analyzed.
Desorption and sublimation kinetics for fluorinated aluminum nitride surfaces
Authors: King Sean W. , Davis Robert F. , Nemanich Robert J.
Published: August 2014

The adsorption and desorption of halogen and other gaseous species from surfaces is a key fundamental process for both wet chemical and dry plasma etch and clean processes utilized in nanoelectronic fabrication processes. Therefore, to increase the fundamental understanding of these processes with regard to aluminum nitride (AlN) surfaces, temperature programmed desorption (TPD) and x-ray photoelectron spectroscopy (XPS) have been utilized to investigate the desorption kinetics of water (H2O), fluorine (F2), hydrogen (H2), hydrogen fluoride (HF), and other related species from aluminum nitride thin film surfaces treated with an aqueous solution of buffered hydrogen fluoride (BHF) diluted in methanol (CH3OH). Pre-TPD XPS measurements of the CH3OH:BHF treated AlN surfaces showed the presence of a variety of Al-F, N-F, Al-O, Al-OH, C-H, and C-O surfaces species in addition to Al-N bonding from the AlN thin film. The primary species observed desorbing from these same surfaces during TPD measurements included H2, H2O, HF, F2, and CH3OH with some evidence for nitrogen (N2) and ammonia (NH3) desorption as well. For H2O, two desorption peaks with second order kinetics were observed at 195 and 460 °C with activation energies (Ed) of 51 ± 3 and 87 ± 5 kJ/mol, respectively. Desorption of HF similarly exhibited second order kinetics with a peak temperature of 475 °C and Ed of 110 ± 5 kJ/mol. The TPD spectra for F2 exhibited two peaks at 485 and 585 °C with second order kinetics and Ed of 62 ± 3 and 270 ± 10 kJ/mol, respectively. These values are in excellent agreement with previous Ed measurements for desorption of H2O from SiO2 and AlFx from AlN surfaces, respectively. The F2 desorption is therefore attributed to fragmentation of AlFx species in the mass spectrometer ionizer. H2 desorption exhibited an additional high temperature peak at 910 °C with Ed = 370 ± 10 kJ/mol that is consistent with both the dehydrogenation of surface AlOH species and H2 assisted sublimation of AlN. Similarly, N2 exhibited a similar higher temperature desorption peak with Ed = 535 ± 40 kJ/mol that is consistent with the activation energy for direct sublimation of AlN.
Association of Navicular Drop and Selected Lower-Limb Biomechanical Measures During the Stance Phase of Running
Authors: Eslami Mansour , Damavandi Mohsen , Ferber Reed
Published: August 2014

There is evidence to suggest that navicular drop measures are associated with specific lower-extremity gait biomechanical parameters. The aim of this study was to examine the relationship between navicular drop and a) rearfoot eversion excursion, b) tibial internal rotation excursion, c) peak ankle inversion moment, and d) peak knee adduction moment during the stance phase of running. Sixteen able-bodied men having an average age of 28.1 (SD = 5.30) years, weight of 81.5 (SD = 10.40) kg, height of 179.1 (SD = 5.42) cm volunteered and ran barefoot at 170 steps/minute over a force plate. Navicular drop measures were negatively correlated with tibial internal rotation excursion (r = −0.53, P = .01) but not with rearfoot eversion excursion (r = −0.19; P = .23). Significant positive correlations were found between navicular drop and peak knee adduction moment (r = .62, P < .01) and peak ankle inversion moment (r = .60, P < .01). These findings suggest that a low navicular drop measure could be associated with increasing tibial rotation excursion while high navicular drop measure could be associated with increased peak ankle and knee joint moments. These findings indicate that measures of navicular drop explained between 28% and 38% of the variability for measures of tibial internal rotation excursion, peak knee adduction moment and peak ankle inversion moments.
The Effects of Walking Speed on Tibiofemoral Loading Estimated Via Musculoskeletal Modeling
Authors: Lerner Zachary F. , Haight Derek J. , DeMers Matthew S. , Board Wayne J. , Browning Raymond C.
Published: August 2014

Net muscle moments (NMMs) have been used as proxy measures of joint loading, but musculoskeletal models can estimate contact forces within joints. The purpose of this study was to use a musculoskeletal model to estimate tibiofemoral forces and to examine the relationship between NMMs and tibiofemoral forces across walking speeds. We collected kinematic, kinetic, and electromyographic data as ten adult participants walked on a dual-belt force-measuring treadmill at 0.75, 1.25, and 1.50 m/s. We scaled a musculoskeletal model to each participant and used OpenSim to calculate the NMMs and muscle forces through inverse dynamics and weighted static optimization, respectively. We determined tibiofemoral forces from the vector sum of intersegmental and muscle forces crossing the knee. Estimated tibiofemoral forces increased with walking speed. Peak earlystance compressive tibiofemoral forces increased 52% as walking speed increased from 0.75 to 1.50 m/s, whereas peak knee extension NMMs increased by 168%. During late stance, peak compressive tibiofemoral forces increased by 18% as speed increased. Although compressive loads at the knee did not increase in direct proportion to NMMs, faster walking resulted in greater compressive forces during weight acceptance and increased compressive and anterior/posterior tibiofemoral loading rates in addition to a greater abduction NMM.
The Validity of Gait Variability and Fractal Dynamics Obtained From a Single, Body-Fixed Triaxial Accelerometer
Authors: Kobsar Dylan , Olson Chad , Paranjape Raman , Barden John M.
Published: August 2014

A single triaxial accelerometer has the ability to collect a large amount of continuous gait data to quantitatively assess the control of gait. Unfortunately, there is limited information on the validity of gait variability and fractal dynamics obtained from this device. The purpose of this study was to test the concurrent validity of the variability and fractal dynamic measures of gait provided by a triaxial accelerometer during a continuous 10 minute walk in older adults. Forty-one healthy older adults were fitted with a single triaxial accelerometer at the waist, as well as a criterion footswitch device before completing a ten minute overground walk. The concurrent validity of six outcome measures was examined using intraclass correlation coefficients (ICC) and 95% limits of agreement. All six dependent variables measured by the accelerometer displayed excellent agreement with the footswitch device. Mean parameters displayed the highest validity, followed by measures of variability and fractal dynamics in stride times and measures of variability and fractal dynamics in step times. These findings suggest that an accelerometer is a valid and unique device that has the potential to provide clinicians with valid quantitative data for assessing their clients’ gait.
To What Extent Does Not Wearing Shoes Affect the Local Dynamic Stability of Walking?: Effect Size and Intrasession Repeatability
Authors: Terrier Philippe , Reynard Fabienne
Published: August 2014

Local dynamic stability (stability) quantifies how a system responds to small perturbations. Several experimental and clinical findings have highlighted the association between gait stability and fall risk. Walking without shoes is known to slightly modify gait parameters. Barefoot walking may cause unusual sensory feedback to individuals accustomed to shod walking, and this may affect stability. The objective was therefore to compare the stability of shod and barefoot walking in healthy individuals and to analyze the intrasession repeatability. Forty participants traversed a 70 m indoor corridor wearing normal shoes in one trial and walking barefoot in a second trial. Trunk accelerations were recorded with a 3D-accelerometer attached to the lower back. The stability was computed using the finite-time maximal Lyapunov exponent method. Absolute agreement between the forward and backward paths was estimated with the intraclass correlation coefficient (ICC). Barefoot walking did not significantly modify the stability as compared with shod walking (average standardized effect size: +0.11). The intrasession repeatability was high (ICC: 0.73–0.81) and slightly higher in barefoot walking condition (ICC: 0.81–0.87). Therefore, it seems that barefoot walking can be used to evaluate stability without introducing a bias as compared with shod walking, and with a sufficient reliability.
Validity and Reliability of an Inertial Sensor for Wheelchair Court Sports Performance
Authors: Mason Barry S. , Rhodes James M. , Goosey-Tolfrey Victoria L.
Published: August 2014

The purpose of the current study was to determine the validity and reliability of an inertial sensor for assessing speed specific to athletes competing in the wheelchair court sports (basketball, rugby, and tennis). A wireless inertial sensor was attached to the axle of a sports wheelchair. Over two separate sessions, the sensor was tested across a range of treadmill speeds reflective of the court sports (1.0 to 6.0 m/s). At each test speed, ten 10-second trials were recorded and were compared with the treadmill (criterion). A further session explored the dynamic validity and reliability of the sensor during a sprinting task on a wheelchair ergometer compared with high-speed video (criterion). During session one, the sensor marginally overestimated speed, whereas during session two these speeds were underestimated slightly. However, systematic bias and absolute random errors never exceeded 0.058 m/s and 0.086 m/s, respectively, across both sessions. The sensor was also shown to be a reliable device with coefficients of variation (% CV) never exceeding 0.9 at any speed. During maximal sprinting, the sensor also provided a valid representation of the peak speeds reached (1.6% CV). Slight random errors in timing led to larger random errors in the detection of deceleration values. The results of this investigation have demonstrated that an inertial sensor developed for sports wheelchair applications provided a valid and reliable assessment of the speeds typically experienced by wheelchair athletes. As such, this device will be a valuable monitoring tool for assessing aspects of linear wheelchair performance.
Early
56
Ni decay gamma rays from SN2014J suggest an unusual explosion
Authors: Diehl Roland , Siegert Thomas , Hillebrandt Wolfgang , Grebenev Sergei A. , Greiner Jochen , Krause Martin , Kromer Markus , Maeda Keiichi , Röpke Friedrich , Taubenberger Stefan
Published: August 2014

Surprise found by γ-ray metal detector

Astronomers commonly use type-Ia supernovae as standard distance measurement tools, though the physics of these bright sources are not fully understood. One product of the thermonuclear explosion is
56
Ni, which probably lies at the heart of the supernova cloud. Diehl
et al.
detected the gamma-ray emission from
56
Ni in SN2014J much earlier than expected, only about 20 days after the initial explosion. This early exposure suggests both an asymmetric event and the production of
56
Ni farther out in the ejecta than predicted. These sources will help astronomers measure distances far beyond where supernovae have been studied.

Science
, this issue p.
1162
Draft Whole-Genome Sequence of OXA-48-Producing Multidrug-Resistant Klebsiella pneumoniae KP_ST11_OXA-48
Authors: Villa Jennifer , Viedma Esther , Brañas Patricia , Mingorance Jesús , Chaves Fernando
Published: August 2014

We present the draft genome sequence of a blood culture isolate of OXA-48-producing
Klebsiella pneumoniae
(sequence type 11 [ST11]) obtained in the course of a hospital outbreak in Spain. Sequence analysis showed 121 genes related to antibiotic and antiseptic resistance, including
bla
OXA-48
, which was located in an IncL/M plasmid.
Genetic Characterization of a Natural Reassortant H3N8 Avian Influenza Virus Isolated from Domestic Geese in Guangxi, Southern China
Authors: Liu Tingting , Xie Zhixun , Song Degui , Luo Sisi , Xie Liji , Li Meng , Xie Zhiqing , Deng Xianweng
Published: August 2014

A H3N8 subtype of avian influenza virus, A/goose/Guangxi/020G/2009(H3N8) (GX020G), was isolated from the Guangxi Province of China in 2009. All eight gene segments of the GX020G strain were sequenced. Sequence analysis indicated that this H3N8 virus is a novel reassortant strain. The genome sequences provide useful information for understanding the epidemiology and molecular characteristics of the H3N8 subtype of influenza virus in southern China.
First Insights into the Genome of the Amino Acid-Metabolizing Bacterium Clostridium litorale DSM 5388
Authors: Poehlein Anja , Alghaithi Hamed S. , Chandran Lenin , Chibani Cynthia M. , Davydova Elena , Dhamotharan Karthikeyan , Ge Wanwan , Gutierrez-Gutierrez David A. , Jagirdar Advait , Khonsari Bahar , Nair Kamal Prakash P. R. , Daniel Rolf
Published: August 2014

Clostridium litorale
is a Gram-positive, rod-shaped, and spore-forming bacterium, which is able to use amino acids such as glycine, sarcosine, proline, and betaine as single carbon and energy sources via Stickland reactions. The genome consists of a circular chromosome (3.41 Mb) and a circular plasmid (27 kb).
A rare presentation of multiple dens invaginatus in maxillary dentition
Authors: Purani Jigar M , Purani Hiral J
Published: August 2014

Dens invaginatus is a developmental disturbance of the tooth and usually occurs in the maxillary lateral incisor of permanent dentition. In this article, a rare case of dens invaginatus affecting multiple permanent maxillary teeth is described.
Unstable C-spine injury with normal C-spine radiographs
Authors: Razaq Mohammed Adris , Broom Terasa
Published: August 2014

There is some controversy surrounding the optimal mode of imaging in trauma patients with suspected cervical (C) spine injury. Various rules (most notably the Canadian C-spine rules and the NEXUS rules) have been designed to help reduce the need for imaging given the poor yield. Some authorities advocate CT for almost all cases whereas others advocate three view radiographs unless the patient is at high risk, in which case CT is the preferred choice. One meta-analysis showed sensitivity of 58% (39–76%) for plain radiographs and 98% for CT in identification of C-spine injuries following blunt trauma. This case report illustrates how very unstable C-spine injuries may not be apparent on plain radiographs and a degree of clinical suspicion may be required for further imaging.
Saving grace: distally pedicled gracilis muscular flap in lower limb salvage
Authors: Amin Kavit , Dempsey Marlese , Ghali Shadi , Grobbelaar Adriaan
Published: August 2014

During the 1970s, the incidence of limb amputation following surgery for sarcoma excision was as high as 50%. Two important developments have led to modern day limb salvage, namely chemotherapy and precision imaging techniques. We present a case of limb salvage in a patient with osteosarcoma plagued with recurrent infection after prosthetic revision. We discuss the use of the distally based pedicled gracilis muscular flap, which has little mention as a reconstructive option for defects around the knee.
Myelitis and optic neuritis induced by a long course of etanercept in a patient with rheumatoid arthritis
Authors: Yokoyama Waka , Takada Kazuki , Miyasaka Nobuyuki , Kohsaka Hitoshi
Published: August 2014

A 64-year-old woman presented with an acute onset of myelitis and optic neuritis after 47 months of etanercept use for rheumatoid arthritis. Etanercept was discontinued and pulse methylprednisolone therapy (1000 mg/day for 3 days) was started, followed by a quick and complete resolution. Demyelination associated with antitumor necrosis factor agents, reported to develop mostly from 1 week to 12 months after the initiation of the agents, could develop after a few years and thus warrants vigilant monitoring.
Tobacco use among designated air pollution victims and its association with lung function and respiratory symptoms: a retrospective cross-sectional study
Authors: Kotaki Kenji , Senjyu Hideaki , Tanaka Takako , Yano Yudai , Miyamoto Naomi , Nishinakagawa Tsuyoshi , Yanagita Yorihide , Asai Masaharu , Kozu Ryo , Tabusadani Mitsuru , Sawai Terumitsu , Honda Sumihisa
Published: August 2014

Objectives

We sought to elucidate the long-term association of tobacco use and respiratory health in designated pollution victims with and without obstructive pulmonary defects.

Design

A retrospective cross-sectional study.

Setting

The register of pollution victims in Kurashiki, Japan.

Participants

730 individuals over 65 years of age previously diagnosed with pollution-related respiratory disease. Patients were classified into four groups according to their smoking status and whether they had obstructive pulmonary disease. We then compared the prevalence of respiratory symptoms and lung function over time between groups.

Primary outcome measures

Spirometry was performed and a respiratory health questionnaire completed in the same season each year for up to 30 years.

Results

Rates of smoking and respiratory disease were high in our sample. Although respiratory function in non-smoking patients did not completely recover, the annual rate of change in lung function was within the normal range (p<0.01). However, smokers had worse lung function and were more likely to report more severe pulmonary symptoms (p<0.01).

Conclusions

Patients’ respiratory function did not fully recover despite improved air quality. Our results suggest that, in the context of exposure to air pollution, tobacco use causes additional loss of lung function and exacerbates respiratory symptoms.
Recombinant human activated protein C for the treatment of severe sepsis and septic shock: a study protocol for incorporating observational evidence using a Bayesian approach
Authors: Zhang Zhongheng
Published: August 2014

Introduction

Activated protein C (aPC) plays a pivotal role in modulating a severe inflammatory response and is thought to be beneficial for patients with sepsis. However, several meta-analyses of randomised controlled trials (RCTs) show that aPC is not significantly associated with improved survival in critically ill patients with sepsis. One suggestion is that these analyses simply ignored observational evidence. The present study aims to quantitatively demonstrate how observational data can alter the findings derived from synthesised evidence from RCTs by using a Bayesian approach.

Methods and analysis

RCTs and observational studies investigating the effect of aPC on mortality outcome in critically ill patients with sepsis will be included. The quality of included RCTs will be assessed by using the Delphi list. Publication bias will be quantitatively analysed by using the traditional Egger regression test and the Begg rank correlation test. Observational data will be used as the informative prior for the distribution of OR. A power transformation of the observational data likelihood will be considered. Observational evidence will be down-weighted by a power of α which takes values from 0 to 1. Trial sequential analysis will be performed to quantify the reliability of data in meta-analysis adjusting significance levels for sparse data and multiple testing on accumulating trials.

Trial registration number

PROSPERO (CRD42014009562).
Evaluation of a new semiautomated external defibrillator technology: a live cases video recording study
Authors: Maes Frédéric , Marchandise Sébastien , Boileau Laurianne , Le Polain de Waroux Jean-Benoît , Scavée Christophe
Published: August 2014

Aim

To determine the effect of a new automated external defibrillator (AED) system connected by General Packet Radio Service (GPRS) to an external call centre in assisting novices in a sudden cardiac arrest situation.

Method

Prospective, interventional study. Layperson volunteers were first asked to complete a survey about their knowledge and ability to give cardiopulmonary resuscitation (CPR) and use an AED. A simulated cardiac arrest scenario using a CPR manikin was then presented to volunteers. A telephone and semi-AED were available in the same room. The AED was linked to a call centre, which provided real-time information to ‘bystanders’ and emergency services via GPRS/GPS technology. The scene was videotaped to avoid any interaction with examiners. A standardised check list was used to record correct actions.

Results

85 volunteers completed questionnaires and were recorded. Mean age was 44±16, and 49% were male; 38 (45%) had prior CPR training or felt comfortable intervening in a sudden cardiac arrest victim; 40% felt they could deliver a shock using an AED. During the scenarios, 56 (66%) of the participants used the AED and 53 (62%) successfully delivered an electrical shock. Mean time to defibrillation was 2 min 29 s. Only 24 (28%) participants dialled the correct emergency response number (112); the live-assisted GPRS AED allowed alerted emergency services in 38 other cases. CPR was initiated in 63 (74%) cases, 26 (31%) times without prompting and 37 (44%) times after prompting by the AED.

Conclusions

Although knowledge of the general population appears to be inadequate with regard to AED locations and recognition, live-assisted devices with GPS-location may improve emergency care.
Periprocedural and mid-term technical and clinical events after flow diversion for intracranial aneurysms
Authors: Burrows Anthony M , Cloft Harry , Kallmes David F , Lanzino Giuseppe
Published: August 2014

Object

Flow diversion has emerged as a promising treatment alternative for cerebral aneurysms. As a new device, treatment-related events and complications are currently being characterized.

Methods

Data on 100 consecutive procedures with the intention to use flow diversion were prospectively collected and analyzed retrospectively.

Results

Ninety-five aneurysms were treated in 93 patients during 100 consecutive procedures in which the intention was to treat an intracranial aneurysm with flow diversion. Death occurred in 1% and permanent morbidity in 1%. However, periprocedural technical complications occurred in 35% of the procedures and included proximal device migration in 12%, incomplete device expansion in 9%, catheter-induced vasospasm in 6%, and artery perforation from the wire in 3%. Perioperative clinical events were seen in 28% (thromboembolism and access site complications were the most common, being observed in 6.5% of patients). Worsened extraocular motility was seen in 5.4% and resolved in 4/5 patients. Mean clinical follow-up was 17 months. There were no late clinical or technical issues resulting in permanent deficits, although one patient suffered worsening ataxia. Overall, using very strict angiographic criteria, complete angiographic obliteration was 50% at 6 months and 69% after 1 year.

Conclusions

Flow diversion for intracranial aneurysms is a safe and effective treatment. Technical and clinical events are common in the perioperative period. Careful perioperative care and proper management of technical and clinical events encountered is key to achieving low morbidity and mortality. Late clinical events can occur but are unlikely to result in permanent complications.
Fat oxidation over a range of exercise intensities: fitness versus fatness
Authors: Croci Ilaria , Hickman Ingrid J. , Wood Rachel E. , Borrani Fabio , Macdonald Graeme A. , Byrne Nuala M.
Published: August 2014

Maximal fat oxidation (MFO), as well as the exercise intensity at which it occurs (Fatmax), have been reported as lower in sedentary overweight individuals but have not been studied in trained overweight individuals. The aim of this study was to compare Fatmax and MFO in lean and overweight recreationally trained males matched for cardiorespiratory fitness (CRF) and to study the relationships between these variables, anthropometric characteristics, and CRF. Twelve recreationally trained overweight (high fatness (HiFat) group, 30.0% ± 5.3% body fat) and 12 lean males (low fatness (LoFat), 17.2% ± 5.7% body fat) matched for CRF (maximal oxygen consumption (V̇O2max) 39.0 ± 5.5 vs. 41.4 ± 7.6 mL·kg–1·min–1, p = 0.31) and age (p = 0.93) performed a graded exercise test on a cycle ergometer. V̇O2max and fat and carbohydrate oxidation rates were determined using indirect calorimetry; Fatmax and MFO were determined with a mathematical model (SIN); and % body fat was assessed by air displacement plethysmography. MFO (0.38 ± 0.19 vs. 0.42 ± 0.16 g·min–1, p = 0.58), Fatmax (46.7% ± 8.6% vs. 45.4% ± 7.2% V̇O2max, p = 0.71), and fat oxidation rates over a wide range of exercise intensities were not significantly different (p > 0.05) between HiFat and LoFat groups. In the overall cohort (n = 24), MFO and Fatmax were correlated with V̇O2max (r = 0.46, p = 0.02; r = 0.61, p = 0.002) but not with % body fat or body mass index (p > 0.05). Fat oxidation during exercise was similar in recreationally trained overweight and lean males matched for CRF. Consistently, substrate oxidation rates during exercise were not related to adiposity (% body fat) but were related to CRF. The benefits of high CRF independent of body weight and % body fat should be further highlighted in the management of obesity.
Influence of ocean ecosystem variation on trophic interactions and survival of juvenile coho and Chinook salmon
Authors: Losee James P. , Miller Jessica A. , Peterson William T. , Teel David J. , Jacobson Kym C.
Published: August 2014

The community of trophically transmitted marine parasites of juvenile coho (Oncorhynchus kisutch) and Chinook (Oncorhynchus tshawytscha) salmon across 8 years (2002–2009) was related to indices of physical and biological ocean conditions and adult returns. When the biomass of lipid-poor, southern origin copepods in the coastal ocean was high during juvenile salmon outmigration from fresh water (April–June), yearling coho and Chinook salmon harbored a different trophically transmitted parasite fauna and exhibited lower survival compared with years when the southern copepod biomass was low. As copepods are key intermediate hosts in many marine parasite life cycles, these results support a trophic linkage between the copepod community and salmon prey. Interannual variation in the parasite community was correlated with survival of coho salmon (r = −0.67) measured 1 year later and adult returns of Upper Columbia River summer and fall Chinook salmon (r = −0.94) 3 years from the time of ocean entry.
Scattering of a scalar relativistic particle by the hyperbolic tangent potential
Authors: Rojas Clara
Published: August 2014

We solve the Klein–Gordon equation in the presence of the hyperbolic tangent potential. The scattering solutions are derived in terms of hypergeometric functions. The reflection, R, and transmission, T, coefficients are calculated in terms of gamma function and, superradiance is discussed, when the reflection coefficient, R, is greater than one.
SNe data analysis in variable speed of light cosmologies without cosmological constant
Authors: Zhang Pengfei , Meng Xinhe
Published: August 2014

In this work, we aim to show the possibilities of the variable speed of light (VSL) theory in explaining the type Ia supernovae (SNe) observations without introducing dark energy. The speed of light is assumed to be scale factor-dependent, which is the most popular assumption in VSL theory. We show the modified calculation of the distance modulus and the validity of the redshift-scale factor relation in VSL theory. Three different models of VSL are tested SNe data-sets with proper constraints on the model parameters. The comparison of the three models and flat ΛCDM in distance modulus is showed. Some basic problems and the difficulties of the confirmation of the VSL theory are also discussed.
Ordovician marginal basin evolution near the palaeo-Pacific east Gondwana margin, Australia
Authors: Quinn C. D. , Percival I. G. , Glen R. A. , Xiao W.-J.
Published: August 2014

Although the Ordovician Macquarie Arc, part of the eastern Lachlan Orogen of southeastern Australia, has long been considered to be an intra-oceanic arc within an accretionary orogen, key characteristics contrast with more typical examples of accreted arcs. Significantly, multiple stacked phases of mafic to intermediate volcanic rocks, with suprasubduction-zone chemistry, are flanked to the east and west by extensive, coeval continental margin turbidite, chert and black shale sequences. By analysing stratigraphic and contact relationships within and between the volcanic rocks, ophiolitic components (
sensu lato
) and turbidite sequences, constrained by precise biostratigraphy, we document a repeated cycle of uplift, upper-plate extension and collapse common to all sequences. This cycle is interpreted as resulting from localized extension (rifting or hyper-extension and lower-crustal delamination) within a continent-margin sequence developed upon an already established marginal or back-arc basin of probable middle to late Cambrian age. Our interpretation provides a counter-example to prevailing arc accretion models by inferring extensional tectonics at the palaeo-Pacific east Gondwana margin during the Ordovician with development of alkalic and calc-alkalic Cu–Au porphyry deposits away from an active arc system.
Mapping and time-lapse analysis of South Arne Chalk fault network using new developments in seismic dip computation
Authors: Astratti D. , Aarre V. , Vejbæk O. V. , White G.
Published: August 2014

In a reservoir, faults at the limit of the seismic resolution can be crucial to explain production history and to optimize field development. However, in most cases the detail required to describe such subtle features depends on the assistance of seismic attributes and semi-automated interpretation techniques. We generated a detailed description of the fault network in the South Arne Chalk Group using a workflow based on a globally consistent computation of the seismic dip. This led to more accurate seismic edge attributes than gained with standard dip estimation techniques. We analysed each fault set and qualitatively assessed its control on fluid flow. Our investigation suggests that the two fracture sets that influence production developed along the same WNW–ESE structural trend and cannot be separated based on the seismic data alone. These faults were active both during and post Chalk deposition. We observe ENE–WSW lineaments that match the pattern of a time-lapse seismic amplitude anomaly associated with water injection. It remains to be verified whether these lineaments could be an extension of overburden faults, as well as whether the increased intensity of the fault network as seen on the 2005 v. the 1995 3D seismic survey was caused by production effects.