bluuebunny/crossref_metadata_2025 huggingface dataset:
Vortex Shedding From Struts in an Annular Exhaust Diffuser
Authors: Fric Thomas F. , Villarreal Reynaldo , Auer Robert O. , James Michael L. , Ozgur Dincer , Staley Terrill K.
Published: February 2015

Results from scale-model experiments and industrial gas turbine tests show that strut vortex shedding in an annular exhaust diffuser can effectively be modified by adding tapered chord to the struts. The struts are bluff bodies at full-speed, no-load conditions, when inlet swirl is close to 60°. Data from wind tunnel tests show that wake Strouhal number is 0.47, larger than that expected for an isolated cylinder wake. This value of Strouhal number agrees with those measured in full-scale exhaust diffusers. Wind tunnel tests showed that a strut with tapered chord most effectively reduced wake amplitudes and shifted shedding frequency. The tapered strut was also effective in reducing shedding amplitude in a scale-model diffuser. Finally, gas turbine tests employing a tapered strut showed significant reductions in unsteady pressure and noise. A major benefit of strut taper is a reduction of noise by uncoupling of vortex shedding from acoustic resonant response.
Mixing of Multiple Jets With a Confined Subsonic Crossflow in a Cylindrical Duct
Authors: Holdeman James D. , Liscinsky David S. , Samuelsen G. Scott , Oechsle Victor L. , Smith Clifford E.
Published: February 2015

This paper summarizes NASA-supported experimental and computational results on the mixing of a row of jets with a confined subsonic crossflow in a cylindrical duct. The studies from which these results were excerpted investigated flow and geometric variations typical of the complex 3-D flowfield in the combustion chambers in gas turbine engines.

The principal observations were that the momentum-flux ratio and the number of orifices were significant variables. Jet penetration was critical, and jet penetration decreased as either the number of orifices increased or the momentum-flux ratio decreased. It also appeared that jet penetration remained similar with variations in orifice size, shape, spacing, and momentum-flux ratio when the number of orifices was proportional to the square-root of the momentum-flux ratio. In the cylindrical geometry, planar variances are very sensitive to events in the near-wall region, so planar averages must be considered in context with the distributions.

The mass-flow ratios and orifices investigated were often very large (mass-flow ratio >1 and ratio of orifice area-to-mainstream cross-sectional area up to 0.5), and the axial planes of interest were sometimes near the orifice trailing edge. Three-dimensional flow was a key part of efficient mixing and was observed for all configurations. The results shown also seem to indicate that non-reacting dimensionless scalar profiles can emulate the reacting flow equivalence ratio distribution reasonably well. The results cited suggest that further study may not necessarily lead to a universal “rule of thumb” for mixer design for lowest emissions, because optimization will likely require an assessment for a specific application.
On the Navier-Stokes Calculation of Separation Bubbles With a New Transition Model
Authors: Sanz Wolfgang , Platzer Max F.
Published: February 2015

Laminar separation bubbles are commonly observed on turbomachinery blades and therefore require effective methods for their prediction. Therefore, a newly developed transition model by Gostelow et al. (1995) is incorporated into an upwind-biased Navier-Stokes code to simulate laminar-turbulent transition in the boundary layer. A study of the influence of the two adjustable parameters of the model, the transition onset location and the spot generation rate, is conducted and it is found that it can predict laminar separation bubbles, measured on a NACA 0012 airfoil. Additional results are presented for separation bubbles in an annular compressor cascade.
Evaluation of a New Design Concept for a Ceramic Flame Tube Under Engine Conditions
Authors: Münz S. , Schulz A. , Wittig S.
Published: February 2015

At the Institut für Thermische Strömungsmaschinen in Karlsruhe new design concepts for thermally high-loaded ceramic gas turbine components were developed. The present concept is based on a load-oriented segmentation in combination with a flexible suspension and thermal insulation of the ceramic structure. The concept was applied to a flame tube for a small gas turbine. In order to ensure real operating conditions, a Klöckner Humboldt Deutz T216 type gas turbine was used as test bed for the ceramic combustor.

The paper gives a description of the combustor and the test rig. Furthermore, experimental results of the engine tests with special emphasis on the liner wall temperature distribution for various steady and transient operating conditions are presented. A major result of the tests is that the design concept proved to be reliable under real engine conditions. After more than 100 hours no failure of the ceramic parts occured. In order to determine the thermal load of the ceramic flame tube under real conditions, the experimental investigations are supported by numerical calculations.
In-Service Degradation of Corrosion Resistant Coatings
Authors: Cheruvu Narayana S. , Carr Thomas J. , Dworak John , Coyle James
Published: February 2015

The rainbow test was performed to evaluate the effects of cooling hole design modifications and the MCrAlY coating deterioration with and without top aluminide. The cooling design modifications considered in this program include a) camberline cooling hole design, b) peripheral cooling hole design with a turbulated leading edge hole and c) peripheral cooling hole design with all turbulated holes. Following approximately 16,700 hours of operation, one blade from each category was removed for metallurgical evaluation. The MCrAlY coating on the camberline cooled blade without the top aluminide and coat had degraded the most at the blade tip region and along a portion of the leading edge. In some regions, the coating on the leading edge of the blade was oxidized through thickness. However, no oxidation of coating was noted on the leading edge of the blade with the MCrAlY with top aluminide coating. The results show that the top aluminide coating and the cooling hole design modifications extend service life of the MCrAlY coating. The coating deterioration results on these blades are correlated with the β NiAl depleted zone in the coating and the oxide thickness at the cooling hole surfaces. Variations of coating degradation and cooling hole surface oxidation among the blades are discussed in terms of estimated service temperatures measured from γ′ particle size. The cooling hole design modifications significantly lower metal temperature and extend service life of the MCrAlY coating.
3D Laser Transit Measurements of the Tip Clearance Vortex in a Compressor Rotor Blade Row
Authors: Foley Andrew C. , Ivey Paul C.
Published: February 2015

This paper describes the structure of the tip clearance flow in a low speed isolated compressor rotor. Pneumatic cobra probes are radially traversed upstream and downstream of the blade row and the time averaged total pressure losses across the blade row calculated. The increase in pressure losses due to the tip clearance flow is clearly seen.

The nature of the tip losses is investigated further using a unique 3D laser transit anemometer to measure velocities and turbulence levels. A 3D representation of the resulting flow field is then constructed using the experimentally measured velocity vectors. With the aid of ‘stream particles’ released into this flow field a vortex structure is then visualised. A section through the path of this vortex assists in showing its development through the blade row.

Due to the co-location of this vortex and the total pressure losses in the passage, it is this vortex which is believed to be responsible for the excess total pressure losses in the tip region.
Choice of the Pseudo-Optimal Configuration of a Cooled Gas-Turbine Blade Based on a Constrained Minimization of the Global Entropy Production Rate
Authors: Natalini Gianni , Sciubba Enrico
Published: February 2015

The problem of determining the optimal configuration of a cooled gas-turbine blade is approached by an entropy minimization technique proposed in previous works by the same authors. The present paper describes the application of the same line of thought to a more complex (and realistic) pseudo-optimization procedure, in which the objective function is again the global entropy generation rate, but two integral constraints are added to the original formulation: the maximum blade temperature (weak constraint) and the overall enthalpy drop of the working fluid in the blade passage (strong constraint). The discontinuous optimization procedure is presented here in an application which resembles a trial-and-error technique, but can be rigorously and formally described and implemented [12].

As a “zero configuration”, a realistic 2-D geometry is considered, and the thermo-fluiddynamic field around it is computed via a standard finite-element code. Then, the entropy generation rates in the blade/fluid system are calculated, and the value of the overall enthalpy drop of the gas as well as the value and location of the maximum blade temperature are recorded. Keeping all other parameters fixed (in particular, maintaining the same cooling air flowrate), the geometry of the blade is slightly “perturbed”, by introducing arbitrary modifications in the blade profile, the number and location of cooling holes, etc. Again, the velocity and temperature fields are computed, and inlet conditions are tuned so that the overall enthalpy drop remains approximately constant and the blade maximum temperature does not exceed a certain assigned value.

An “optimal” configuration is found, which is affected by the minimal entropy generation rate, while abiding to the imposed constraints.

The procedure is demonstrated on a realistic blade profile, and is shown to produce a better performing cascade, at least in this 2-D simulation. The extension to 3-D problems is — in principle — straightforward (but see Section 3 for further comments).
Internal Damage Accumulation and Imminent Failure of an Industrial Gas Turbine Blade: Interpretation and Implications
Authors: Wood M. I.
Published: February 2015

The row 1 blade from a heavy industrial gas turbine has been examined after ∼21,000 fired hours to assess the level and nature of the damage originating from the cooling holes. This consisted primarily of creep cracking/voiding coupled with deep internal oxidation/nitridation.

The difficulties the manufacturer had in addressing the problem are discussed within the context of component assessment methodologies and the ‘new’ technologies which are being incorporatd into new unit types, but for which little service experience has yet been generated.
Platinum Substitutes and Two-Phase-Glass Overlayers as Low Cost Alternatives to Platinum Aluminide Coatings
Authors: Prasad B. Durga , Sankaran Sankara N. , Wiedemann Karl E. , Glass David E.
Published: February 2015

The feasibility of processing less-expensive alternative coatings to platinum aluminide was examined. Three approaches were followed: 1) enhancement of nickel-aluminide coatings by application of sol-gel derived two-phase-glass (TPG) overlayers, 2) evaluation of TPG coatings on bare IN 738LC, and 3) substitution of Pt with a less expensive platinum group metal (palladium). Accordingly, IN 738LC coupons were tested with several coatings including TPG, aluminide coatings (platinum aluminide, palladium aluminide, and conventional nickel aluminide), and TPG overlayers on the aluminide coatings. Isothermal-oxidation, cyclic-oxidation, and hot-corrosion tests were conducted at 900°C for 500 hours to evaluate the coatings. The results showed that the TPG by itself provided superior protection compared to the platinum-aluminide coatings under both oxidation and hot-corrosion conditions. The TPG coating also showed promise as an overcoat on aluminide coatings.
Prediction of Flow Behaviour and Performance of Squirrel-Cage Centrifugal Fans Operating at Medium and High Flow Rates
Authors: Kind R. J.
Published: February 2015

This paper describes a method for predicting flow behaviour and performance for centrifugal fans of the squirrel-cage type. The work is directed at improving understanding of the factors affecting performance of these fans. A simulation approach has been adopted. That is, the fan is sub-divided into a number of zones (inlet zone, blading zone, volute zone) and the zones are divided into elements. Flow behaviour in the zones and elements and interactions between them are modelled using appropriate equations and correlations. The blading correlations make use of new experimental data for high-solidity cascades of bent sheet metal blades, typical of squirrel-cage fans. Predicted fan performance characteristics are in reasonable agreement with experimental results for flow rates at and above the best-efficiency operating point. Although relatively simple, the method recognizes the main flow phenomena and interactions that occur in squirrel-cage fans and it thus represents a substantial advance over what is currently available in the literature. Together with earlier experimental work, development of the method has provided considerable insight into the relative importance of various aspects of flow behaviour. The ability to deal with extensive reverse flow through the rotor blading has not yet been incorporated and it is evident that this ability is essential for realistic prediction of flow behaviour and performance at below-design flow rates.
HP/HVOF as a Low Cost Substitute for LPPS Turbine MCrAlY Coatings
Authors: Honick Ronald J. , Thorpe Richard
Published: February 2015

MCrAlY (M=Co, Ni) coatings have long been used in gas turbines to protect hot section components from hot corrosion and oxidation. Their complex chemistries, along with the thickness of the deposits, makes them reliable over long periods of time in engines used in power generation and in aircraft applications. A variety of techniques such as Electron Beam Physical Vapor Deposition (EBPVD), Low Pressure Plasma Spray (LPPS), and Argon Shrouded Plasma Spray have been used to deposit MCrAlYs over the years. Until recently, OEM’s have been reluctant to consider alternate deposition methods, but the prospect of lower cost, high quality coatings has merited reconsideration of some long-standing assumptions. In recent efforts, Howmet Thermatech has gained production approval to deposit a proprietary MCrAlY composition on an OEM’s latest generation gas turbine engine components using a TAFA JP-5000 High Pressure/High Velocity Oxygen Fuel (HP/HVOF) coating system. Tensile bond and hardness data are presented which substantiate the equivalence of this coating to its VPX® forerunner. Photomicrographs illustrate the levels of porosity, oxide content and interface quality currently in revenue service. Unpublished cost data from an established coating supplier reveal that MCrAlYs can be deposited by HP/HVOF at a fraction of the cost of VPX® alternatives.
Wall-Jet Turbulent Boundary Layer Heat Flux, Velocity, and Temperature Spectra and Time Scales
Authors: Holmberg David G. , Pestian David J.
Published: February 2015

The interactions of boundary layer flow temperature fluctuations (t′) and velocity fluctuations (u′, v′) together with surface heat flux fluctuations (q′) have been investigated experimentally in a flat plate turbulent boundary layer in order to better understand time-resolved interactions between flow unsteadiness and surface heat flux. A Heat Flux Microsensor (HFM) was placed on a heated flat plate beneath a turbulent wall jet, and a split-film boundary layer probe was traversed above it together with a cold-wire temperature probe. The recorded simultaneous time-resolved u′v′t′q′ data can be correlated across the boundary layer. Results indicate that wall heat transfer (both mean and fluctuating components) is controlled by the u′ fluctuating velocity field. In the presence of high free-stream turbulence (FST), the heat flux is largely controlled by free stream eddies of large size and energy reaching deep into the boundary layer, such that heat flux spectra can be determined from the free-stream velocity field. This is evidenced by uq coherence present across the boundary layer, as well as by similarity in heat flux and u velocity spectra, and by the presence of large velocity scales down to the nearest wall measuring location just above the laminar sublayer.
Repowering a Steam Turbine-Generator Power Plant Through Heat Recovery Type Combined Cycle: Selection of the Cycle — A Case Study
Authors: Bazzini H. A.
Published: February 2015

Much of the steam-turbine based, power generating units all over the word are more than 30 years old now. Within a few years they will face the possibility of retirement from service and replacement. Nonetheless some of them are firm candidates for repowering, a technology able to improve plant efficiency, output and reliability at low costs.

This paper summarizes a study performed to establish the feasibility to repower a 2 × 33 MW steam turbine power plant and the procedure followed until selection of the steam cycle more suitable to the project. The preferred solution is compared with direct replacement of the units by a new combined cycle.

Various repowering options were reviewed to find “beat recovery” type repowering as the best solution. That well-known technology consists of replacing the steam generator by a gas turbine coupled to an HRSG, supplying steam to the existing steam turbine.

Three “GT+HRSG+ST” arrangements were considered. Available gas turbine-generators — both industrial and aero-derivative type —, were surveyed for three power output ranges. Five “typical” gas turbine-generator classes were then selected.

Steam flow raised at the HRSG, gross and net power generation, and heat exchanging surface area of the HRSG, were calculated for a broad range of usually applied, steam turbine throttle conditions. Both single pressure and double pressure steam cycles were considered, as well as supplemental fire and convenience of utilizing the existing feed water heaters. Balance of plant constraints were also reviewed.

Estimates were developed for total investment, O&M costs, fuel expenses, and revenues. Results are shown through various graphics and tables. The route leading to the preferred solution is explained and a sensitivity analysis added to validate the selection.

The preferred solution, consisting in a Class 130 gas turbine in arrangement 1–1–2, a dual-pressure HRSG and a steam cycle without feed-water heaters, win allow delivering 200 MW to the grid, with a heat rate of 7423 kJ/kW-hr. Investment was valued at $MM77.0, with an IRR of 15.3%. Those figures compare well with the option of installing a new GTCC unit: with a better heat rate but an investment valued at $MM97.5, its IRR will only be 12.4%.
Time and Cycle Dependence in High Temperature Fatigue of Ceramic Matrix Composites
Authors: Steen Marc , Vallés José-Lorenzo
Published: February 2015

The high temperature fatigue behaviour of two 2D reinforced ceramic matrix composites (CMCs) Is studied under high vacuum conditions. The mechanical loads imposed result in matrix cracking upon first loading, so that continued cyclic loading results in progressive interfacial debonding and/or matrix crack multiplication, as well as fibre failure. In order to investigate whether the fatigue life is mainly governed by time-dependent creep or by cyclically induced fatigue damage, a range of frequencies and two stress ratios are explored in stress controlled fatigue tests. The results obtained indicate that under pulsating fatigue (positive stress ratios or tension-tension) the material response is affected by both creep and fatigue mechanisms. The cyclic damage component gains in relative importance with increasing test frequency. Under reversed loading conditions (negative stress ratios), and depending on the creep strength mismatch between the fibres and the matrix, the time-dependent damage component can be largely suppressed, and the composite fatigue behaviour can become close to purely cycle-dependent. In both cases and for both composites fatigue failure is triggered by fibre failure.
Comparison of k-ε Models in Predicting Heat Transfer and Skin Friction Under High Free Stream Turbulence
Authors: Iyer Ganesh R. , Yavuzkurt Savash
Published: February 2015

Calculations of the effects of high free stream turbulence (FST) on heat transfer and skin friction in a flat plate turbulent boundary layer using different k-ε models (Launder-Sharma, K-Y Chien, Lam-Bremhorsi and Jones-Launder) are presented. This study was carried out in order to investigate the prediction capabilities of these models under high FST conditions. In doing so, TEXSTAN, a partial differential equation solver which is based on the ideas of Patankar and Spalding and solves steady-flow boundary layer equations, was used. Firstly, these models were compared as to how they predicted very low FST (≤ 1% turbulence intensity) cases. These baseline cases were tested by comparing predictions with both experimental data and empirical correlations. Then, these models were used in order to determine the effect of high FST (>5% turbulence intensity) on heat transfer and skin friction and compared with experimental data. Predictions for heat transfer and skin friction coefficient for all the turbulence intensities tested by all the models agreed well (within 1–8%) with experimental data. However, all these models predicted poorly the dissipation of turbulent kinetic energy (TKE) in the free stream and TKE profiles. Physical reasoning as to why the aforementioned models differ in their predictions and the probable cause of poor prediction of free-stream TKE and TKE profiles are given.
Three-Dimensional Flow Calculations of the Stator in a Highly Loaded Transonic Fan
Authors: Emmerson Paul R.
Published: February 2015

A 3D viscous solver has been used to model the flow in the stator of a highly loaded single-stage transonic fan. The fan has a very high level of aerodynamic loading at the hub, which results in a severe hub endwall stall. Prediction of the flow at the 100% speed, peak efficiency condition has been carried out and comparisons are made with experiment, including stator exit traverses and fixed blade surface pressure tappings and flow visualisation. Comparisons are also made with an analysis of the rotor and stator rows using the DRA S1-S2 method.

The 3D predictions show good qualitative agreement with measurements in all regions of the flow field. Quantitatively the flow away from the hub region agreed the best. The general trends of the severe hub endwall stail were predicted, although the shape and size did not match experiment exactly. The S1-S2 system was unable to predict the hub endwall stall, since it arises from fully 3D flow effects.
Effects of Core-Musculature Fatigue on Maximal Shoulder Strength
Authors: Rosemeyer James R. , Hayes Bradley T. , Switzler Craig L. , Hicks-Little Charlie A.
Published: February 2015

Context:

Core stability has been shown to affect lower-extremity motion, but activation of the core has also been observed just before movements of the upper extremity. However, there is limited evidence regarding the effects that core musculature has on upper-extremity strength.

Objective:

To determine the effects of core fatigue on maximal shoulder strength.

Design:

Crossover study.

Setting:

Sports-medicine research laboratory.

Participants:

23 participants (15 male and 8 female, age 21.3 ± 2.5 y, height 174.5 ± 10.3 cm, weight 71.3 ± 12.0 kg).

Intervention:

All participants performed maximal voluntary isometric contractions in 3 different planes (sagittal, frontal, transverse) of shoulder-joint motion. A core-fatiguing protocol was conducted, and the same 3 shoulder-strength tests were repeated and compared with the initial measurements.

Main Outcome Measures:

Strength measures were recorded in kilograms with a dynamometer.

Results:

Results showed a significant decrease in strength in the frontal (−0.56 ± 1.06 kg, P = .020) and transverse (−0.89 ± 1.49 kg, P = .012) planes but not in the sagittal plane (−0.20 ± 0.98 kg, P > .05). Furthermore, regardless of the specific strength test measured, results revealed that the 1st (−7.05% ± 11.65%, P = .012) and 2nd (−5.71% ± 12.03%, P = .042) strength-test measurements after the fatiguing protocol were significantly decreased, while the 3rd strength-test measurement (−4.19% ± 12.48%, P = .140) did not show statistical significance.

Conclusion:

These results indicate that decrease in core stability may have an influence on shoulder strength. The literature suggests that the core is designed for endurance, and this study helps validate its recovery properties. Further research is needed to determine the significance of this effect and how injury rates coincide.
Reliability of 3-Dimensional Measures of Single-Leg Drop Landing Across 3 Institutions: Implications for Multicenter Research for Secondary ACL-Injury Prevention
Authors: Myer Gregory D. , Bates Nathaniel A. , DiCesare Christopher A. , Foss Kim D. Barber , Thomas Staci M. , Wordeman Samuel C. , Sugimoto Dai , Roewer Benjamin D. , McKeon Jennifer M. Medina , Di Stasi Stephanie L. , Noehren Brian W. , McNally Michael , Ford Kevin R. , Kiefer Adam W. , Hewett Timothy E.
Published: February 2015

Context:

Due to the limitations of single-center studies in achieving appropriate sampling with relatively rare disorders, multicenter collaborations have been proposed to achieve desired sampling levels. However, documented reliability of biomechanical data is necessary for multicenter injury-prevention studies and is currently unavailable.

Objective:

To measure the reliability of 3-dimensional (3D) biomechanical waveforms from kinetic and kinematic variables during a single-leg landing (SLL) performed at 3 separate testing facilities.

Design:

Multicenter reliability study.

Setting:

3 laboratories.

Patients:

25 female junior varsity and varsity high school volleyball players who visited each facility over a 1-mo period.

Intervention:

Subjects were instrumented with 43 reflective markers to record 3D motion as they performed SLLs. During the SLL the athlete balanced on 1 leg, dropped down off of a 31-cm-high box, and landed on the same leg. Kinematic and kinetic data from both legs were processed from 2 trials across the 3 laboratories.

Main Outcome Measures:

Coefficients of multiple correlations (CMC) were used to statistically compare each joint angle and moment waveform for the first 500 ms of landing.

Results:

Average CMC for lower-extremity sagittal-plane motion was excellent between laboratories (hip .98, knee .95, ankle .99). Average CMC for lower-extremity frontal-plane motion was also excellent between laboratories (hip .98, knee .80, ankle .93). Kinetic waveforms were repeatable in each plane of rotation (3-center mean CMC ≥.71), while knee sagittal-plane moments were the most consistent measure across sites (3-center mean CMC ≥.94).

Conclusions:

CMC waveform comparisons were similar relative to the joint measured to previously published reports of between-sessions reliability of sagittal- and frontal-plane biomechanics performed at a single institution. Continued research is needed to further standardize technology and methods to help ensure that highly reliable results can be achieved with multicenter biomechanical screening models.
Unexpected-Disturbance Program for Rehabilitation of High-Performance Athletes
Authors: Teichmann Jorg , Suwarganda Edin K. , Lendewig Claudia , Wilson Barry D. , Yeo Wee Kian , Aziz Ramlan Abdul , Schmidtbleicher Dietmar
Published: February 2015

Context:

The Unexpected-Disturbance Program (UDP) promotes exercises in response to so-called involuntary short- to midlatency disturbances.

Objective:

This study investigated the effectiveness of the UDP in the last 6 wk of rehabilitation.

Design:

Pre–post study with 2-tailed paired t tests for limited a priori comparisons to examine differences.

Setting:

National Sports Institute of Malaysia.

Participants:

24 Malaysian national athletes.

Interventions:

7 sessions/wk of 90 min with 3 sessions allocated for 5 or 6 UDP exercises.

Main Outcomes:

Significant improvements for men and women were noted. Tests included 20-m sprint, 1-repetition-maximum single-leg press, standing long jump, single-leg sway, and a psychological questionnaire.

Results:

For men and women, respectively, average strength improvements of 22% (d = 0.96) and 29% (d = 1.05), sprint time of 3% (d = 1.06) and 4% (d = 0.58), and distance jumped of 4% (d = 0.59) and 6% (d = 0.47) were noted. In addition, athletes reported improved perceived confidence in their abilities. All athletes improved in each functional test except for long jump in 2 of the athletes. Mediolateral sway decreased in 18 of the 22 athletes for the injured limb.

Conclusion:

The prevention training with UDP resulted in improved conditioning and seems to decrease mediolateral sway.
Complete Genome Sequence of the Unclassified Iron-Oxidizing, Chemolithoautotrophic
Burkholderiales
Bacterium GJ-E10, Isolated from an Acidic River
Authors: Fukushima Jun , Tojo Fuyumi , Asano Ryoki , Kobayashi Yayoi , Shimura Yoichiro , Okano Kunihiro , Miyata Naoyuki
Published: February 2015

Burkholderiales bacterium GJ-E10, isolated from the Tamagawa River in Akita Prefecture, Japan, is an unclassified, iron-oxidizing chemolithoautotrophic bacterium. Its single circular genome, consisting of 3,276,549 bp, was sequenced by using three types of next-generation sequencers and the sequences were then confirmed by PCR-based Sanger sequencing.
Draft Genome Sequences of Mycobacterium setense Type Strain DSM-45070 and the Nonpathogenic Strain Manresensis, Isolated from the Bank of the Cardener River in Manresa, Catalonia, Spain
Authors: Rech Gabriel , Vilaplana Cristina , Velasco Juan , Pluvinet Raquel , Santín Sheila , Prat Cristina , Julián Esther , Alcaide Fernando , Comas Iñaki , Sumoy Lauro , Cardona Pere-Joan
Published: February 2015

We present here the draft genome sequences of twoMycobacterium setensestrains. One of them corresponds to the M. setense type strain DSM-45070, originally isolated from a patient with a posttraumatic chronic skin abscess. The other one corresponds to the nonpathogenic M. setense strain Manresensis, isolated from the Cardener River crossing Manresa, Catalonia, Spain. A comparative genomic analysis shows a smaller genome size and fewer genes in M. setense strain Manresensis relative to those of the type strain, and it shows the genome segments unique to each strain.
Complete Genome Sequence of the Novel Leech Symbiont Mucinivorans hirudinis M3
T
Authors: Nelson Michael C. , Bomar Lindsey , Graf Joerg
Published: February 2015

Mucinivorans hirudinis
M3
T
was isolated from the digestive tract of the medicinal leech,
Hirudo verbana
, and is the type species of a new genus within the
Rikenellaceae
. Here, we report the complete annotated genome sequence of this bacterium.
Draft Genome Sequence of a Quorum-Sensing Bacterium, Dickeya sp. Strain 2B12, Isolated from a Freshwater Lake
Authors: Tan Kian-Hin , Sheng Kit-Yeng , Chang Chien-Yi , Yin Wai-Fong , Chan Kok-Gan
Published: February 2015

Dickeya sp. strain 2B12 was isolated from a freshwater lake in Malaysia. Here, we report the draft genome sequence of Dickeya sp. 2B12 sequenced by the Illumina MiSeq platform. With the genome sequence available, this genome sequence will be useful for the study of quorum-sensing activity in this isolate.
Approximate Planning in POMDPs with Weighted Graph Models
Authors: Lin Yong , Lu Xingjia , Makedon Fillia
Published: February 2015

Markov decision process (MDP) based heuristic algorithms have been considered as simple, fast, but imprecise solutions for partially observable Markov decision processes (POMDPs). The main reason comes from how we approximate belief points. We use weighted graphs to model the state space and the belief space, in order for a detailed analysis of the MDP heuristic algorithm. As a result, we provide the prerequisite conditions to build up a robust belief graph. We further introduce a dynamic mechanism to manage belief space in the belief graph, so as to improve the efficiency and decrease the space complexity. Experimental results indicate our approach is fast and has high quality for POMDPs.
A brief note on energy from graphene
Authors: Sidharth B. G.
Published: February 2015

We comment briefly on a possible energy source from graphene, arising out of the anomalous behavior of a beam of protons in it.
Comparative study of alpha + nucleus elastic scattering using different models
Authors: Al-Ghamdi A. H. , Ibraheem Awad A. , El-Azab Farid M.
Published: February 2015

The alpha (α) elastic scattering from different targets potential over the energy range 10–240 MeV has been analyzed in the framework of the single-folding (SF) optical model. Four targets are considered, namely, 24 Mg , 28 Si , 32 S and 40 Ca . The SF calculations for the real central part of the nuclear optical potential are performed by folding an effective α–α interaction with the α-cluster distribution density in the target nucleus. The imaginary part of the optical potential is expressed in the phenomenological Woods–Saxon (WS) form. The calculated angular distributions of the elastic scattering differential cross-section using the derived semimicroscopic potentials successfully reproduce 36 sets of data all over the measured angular ranges. The obtained results confirm the validity of the α-cluster structure of the considered nuclei. For the sake of comparison, the same sets of data are reanalyzed using microscopic double-folded optical potentials based upon the density-dependent Jeukenne–Lejeune–Mahaux (JLM) effective nucleon–nucleon interaction.
Systematic nonlocal optical model potential for nucleons
Authors: Tian Yuan , Pang Dan-Yang , Ma Zhong-Yu
Published: February 2015

Based on the Perey–Buck nonlocal optical model potential, F. Perey and B. Buck, Nucl. Phys. 32 (1962) 353, we obtain a new set of nonlocal optical model potential (NLOMP) parameters for proton and neutron scattering off nuclei. The experimental angular distributions of nucleon scattering off nuclei ranging from 27 Al to 208 Pb with incident energies around 10 MeV to 30 MeV are adopted in the fitting procedures. This NLOMP is energy independent. The chi-squares χ2 obtained in the fittings are comparable to those from the KD03 phenomenological local optical model potentials (OMP) A. Koning and J. Delaroche, Nucl. Phys. A 713 (2003) 231. Good agreement is found in comparisons between optical model calculations using this NLOMP and KD03 in their reproduction to the experimental angular distributions of elastic scattering cross-sections and analyzing powers.
FACTORS LEADING TO LATERAL ANKLE SPRAIN: A REVIEW OF THE LITERATURE
Authors: Raina Shakti , Nuhmani Shibili
Published: February 2015

Objective of the review is to get to know the different factors which leads to the most common injury associated with sports persons to the ankle that is the lateral ankle sprain. Many factors cause ankle sprain — gender (whether females are more predisposed to ankle sprain than males); anthropometric variability and limb dominance, muscle strength including evertors–invertor's strength and pro-activation of peroneal muscles. Previous episode of ankle sprain also affects the stability as it alters the proprioception leading to impaired neuromuscular facilitation. Joint laxity (pathological — due to injury and nonpathological — generalized body laxity) is also considered as another causative factor. Type and duration of the game or putting the assistive device during the game or training also contribute to the ankle sprain. By knowing the predisposing factors, athletes will be given more specific rehabilitation according to their risk factor, especially focusing on their advance rehabilitation. Athletes can also be taught to take the preventive measures by determining their risk factor and preparing according to it.
Facile transformation of the five-membered exocyclic E-ring in 132-demethoxycarbonyl chlorophyll derivatives by molecular oxygen with titanium oxide in the dark
Authors: Takahashi Naoya , Hirota Keiya , Saga Yoshitaka
Published: February 2015

Major photosynthetic pigments chlorophyll(Chl)s have a cyclic tetrapyrrole with a five-membered exocyclic E-ring as photofunctional moieties. Its transformation is one promising methodology to develop functional pigments based on Chl chemistry. This paper report a facile conversion from Chl derivatives lacking the 132-methoxycarbonyl moiety to the corresponding chlorophyllous pigments, whose exocyclic E-ring had two oxo groups at the 131- and 132-positions, by contact with the TiO 2 particles in the presence of molecular oxygen in the dark. The conversion proceeded under mild conditions without hydrolysis of the ester group in the 17-propionate residue. This is in sharp contrast to the inevitable ester cleavage in the conventional synthesis of Chl derivatives that possess α-diketone in the E-ring. The reaction properties in the present method allowed us to perform a one-step conversion of Chl derivatives esterified with a natural isoprenoid alcohol phytol to the corresponding 132-oxo-pigments. No removal of central Zn from the chlorin macrocycle occurred in the present conversions using Zn pyropheophytin a as a starting material.
3-Hitting set on bounded degree hypergraphs: Upper and lower bounds on the kernel size
Authors: Kanj Iyad , Zhang Fenghui
Published: February 2015

We study upper and lower bounds on the vertex-kernel size for the 3-HITTING SET problem on hypergraphs of degree at most 3, denoted 3-3-HS. We first show that, unless P = NP, 3-3-HS on 3-uniform hypergraphs does not have a vertex-kernel of size at most 35k/19 > 1.8421k. We then give a 4k - k0.2692 vertex-kernel for 3-3-hs that is computable in time O(k2). We do not assume that the hypergraph is 3-uniform for the vertex-kernel upper bound results. This result improves the upper bound of 4k on the vertex-kernel size for 3-3-HS, implied by the results of Wahlström.
On permutability graphs of subgroups of groups
Authors: Rajkumar R. , Devi P.
Published: February 2015

The permutability graph of subgroups of a given group G, denoted by Γ(G), is a graph with vertex set consists of all the proper subgroups of G and two distinct vertices in Γ(G) are adjacent if and only if the corresponding subgroups permute in G. In this paper, we classify the finite groups whose permutability graphs of subgroups are one of bipartite, star graph, C3-free, C5-free, K4-free, K5-free, K1,4-free, K2,3-free or Pn-free (n = 2, 3, 4). We investigate the same for infinite groups also. Moreover, some results on the girth, completeness and regularity of the permutability graphs of subgroups of groups are obtained. Among the other results, we characterize groups Q8, S3 and A4 by using their permutability graphs of subgroups.
Mechanism by which shock wave lithotripsy can promote formation of human calcium phosphate stones
Authors: Evan Andrew P. , Coe Fredric L. , Connors Bret A. , Handa Rajash K. , Lingeman James E. , Worcester Elaine M.
Published: February 2015

Human stone calcium phosphate (CaP) content correlates with higher urine CaP supersaturation (SS) and urine pH as well as with the number of shock wave lithotripsy (SWL) treatments. SWL does damage medullary collecting ducts and vasa recta, sites for urine pH regulation. We tested the hypothesis that SWL raises urine pH and therefore Cap SS, resulting in CaP nucleation and tubular plugging. The left kidney (T) of nine farm pigs was treated with SWL, and metabolic studies were performed using bilateral ureteral catheters for up to 70 days post-SWL. Some animals were given an NH4Cl load to sort out effects on urine pH of CD injury vs. increased HCO3−delivery. Histopathological studies were performed at the end of the functional studies. The mean pH of the T kidneys exceeded that of the control (C) kidneys by 0.18 units in 14 experiments on 9 pigs. Increased HCO3−delivery to CD is at least partly responsible for the pH difference because NH4Cl acidosis abolished it. The T kidneys excreted more Na, K, HCO3−, water, Ca, Mg, and Cl than C kidneys. A single nephron site that could produce losses of all of these is the thick ascending limb. Extensive injury was noted in medullary thick ascending limbs and collecting ducts. Linear bands showing nephron loss and fibrosis were found in the cortex and extended into the medulla. Thus SWL produces tubule cell injury easily observed histopathologically that leads to functional disturbances across a wide range of electrolyte metabolism including higher than control urine pH.
Individual response to exercise training - a statistical perspective
Authors: Hecksteden Anne , Kraushaar Jochen , Scharhag-Rosenberger Friederike , Theisen Daniel , Senn Stephen , Meyer Tim
Published: February 2015

In the era of personalized medicine, interindividual differences in the magnitude of response to an exercise training program (subject-by-training interaction; “individual response”) have received increasing scientific interest. However, standard approaches for quantification and prediction remain to be established, probably due to the specific considerations associated with interactive effects, in particular on the individual level, compared with the prevailing investigation of main effects. Regarding the quantification of subject-by-training interaction in terms of variance components, confounding sources of variability have to be considered. Clearly, measurement error limits the accuracy of response estimates and thereby contributes to variation. This problem is of particular importance for analyses on the individual level, because a low signal-to-noise ratio may not be compensated by increasing sample size (1 case). Moreover, within-subject variation in training efficacy may contribute to gross response variability. This largely unstudied source of variation may not be disclosed by comparison to a control group but calls for repeated interventions. A second critical point concerns the prediction of response. There is little doubt that exercise training response is influenced by a multitude of determinants. Moreover, indications of interaction between influencing factors of training efficacy lead to the hypothesis that optimal predictive accuracy may be attained using an interactive rather than additive approach. Taken together, aiming at conclusive inference and optimal predictive accuracy in the investigation of subject-by-training interaction entails specific requirements that are deducibly based on statistical principles but beset with many practical difficulties. Therefore, pragmatic alternatives are warranted.
Electrical Power Analysis Using the Scattering Bond Graph
Authors: Tapia-Sánchez Roberto
Published: February 2015

The perspective of the well known concept of active and reactive power in electrical systems is addressed in this paper. This concept is presented from the point of view of the bond graph methodology. The scattering matrix concept is used in order to deal with these formulations. The concept of active and reactive power is presented with some examples derived from single-phase AC circuits. The formulations and simulations of these circuits are presented.
Polymorphisms inMIR27AAssociated with Early-Onset Toxicity in Fluoropyrimidine-Based Chemotherapy
Authors: Amstutz Ursula , Offer Steven M. , Sistonen Johanna , Joerger Markus , Diasio Robert B. , Largiadèr Carlo R.
Published: February 2015

Purpose: The microRNA miR-27a was recently shown to directly regulate dihydropyrimidine dehydrogenase (DPD), the key enzyme in fluoropyrimidine catabolism. A common polymorphism (rs895819A>G) in the miR-27a genomic region (MIR27A) was associated with reduced DPD activity in healthy volunteers, but the clinical relevance of this effect is still unknown. Here, we assessed the association of MIR27A germline variants with early-onset fluoropyrimidine toxicity.

Experimental Design: MIR27A was sequenced in 514 patients with cancer receiving fluoropyrimidine-based chemotherapy. Associations of MIR27A polymorphisms with early-onset (cycles 1–2) fluoropyrimidine toxicity were assessed in the context of known risk variants in the DPD gene (DPYD) and additional covariates associated with toxicity.

Results: The association of rs895819A>G with early-onset fluoropyrimidine toxicity was strongly dependent on DPYD risk variant carrier status (Pinteraction = 0.0025). In patients carrying DPYD risk variants, rs895819G was associated with a strongly increased toxicity risk [OR, 7.6; 95% confidence interval (CI), 1.7–34.7; P = 0.0085]. Overall, 71% (12/17) of patients who carried both rs895819G and a DPYD risk variant experienced severe toxicity. In patients without DPYD risk variants, rs895819G was associated with a modest decrease in toxicity risk (OR, 0.62; 95% CI, 0.43–0.9; P = 0.012).

Conclusions: These results indicate that miR-27a and rs895819A>G may be clinically relevant for further toxicity risk stratification in carriers of DPYD risk variants. Our data suggest that direct suppression of DPD by miR-27a is primarily relevant in the context of fluoropyrimidine toxicity in patients with reduced DPD activity. However, miR-27a regulation of additional targets may outweigh its effect on DPD in patients without DPYD risk variants. Clin Cancer Res; 21(9); 2038–44. ©2015 AACR.
Modification of Cell Differentiation, One of the Mechanisms in the Surveillance of Malignancy
Authors: Klein Eva , Nagy Noemi , Rasul Eahsan
Published: February 2015

Most humans carry the potentially life-endangering Epstein–Barr virus (EBV). The immediate danger after infection is imposed by proliferation of the B cells that carry the viral genome. Although a number of different cell types can be infected with EBV, B lymphocytes are exceptionally sensitive; they express a set of virus-encoded proteins, which collaborate with host proteins to induce proliferation. This phenomenon can be demonstrated in vitro with experimentally infected B cells. These viral genes are expressed only in B lymphocytes and are restricted to a defined differentiation stage. This limitation is of high importance for the maintenance of the controlled EBV-carrier state of humans. The emergence of EBV-induced B-cell malignancies is counteracted by highly efficient immunologic mechanisms. Recognition of EBV-transformed immunoblasts in an MHC class I–restricted manner by cytotoxic CD8 T cells and, to a lesser extent, by CD4 T cells, is thought to play the major role. The in vitro experimental results are in accordance with the emergence of EBV+ B-cell malignancies in immunosuppressive conditions. In this Masters primer, we emphasize that in addition to eliminating B cells that carry the virus genome, the regulatory circuit of the immune response also operates in surveillance, particularly in the early phase of infection. This mechanism involves T-cell–mediated regulation of B-cell differentiation. Because of the strict dependence of the viral growth program on the expression of host cell factors, altering the differentiation state can curb the proliferation of B cells that harbor the viral genome. Cancer Immunol Res; 3(2); 97–102. ©2015 AACR.