bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimisation of Boat-Tails for Heavy Vehicles
Authors: Burton David , Nazarinia Mehdi , Sheridan John , Parkin Derwin
Published: June 2012

Boat-tails offer significant promise in reducing long haul heavy vehicle aerodynamic drag, and hence fuel consumption and greenhouse gas emissions. This paper presents results from a basic numerical and experimental investigation of drag coefficient reductions for various boat-tail configurations. The vehicle chosen is an arbitrary streamlined front end with a width to height ratio of 64%. No tractor to trailer gap is modeled. Approximate model scale is 12% and test Reynolds Number is ∼850,000. Experimental data and numerical simulations are presented for the zero yaw angle condition. For boat-tail angles where the flow remains largely attached a relationship is observed between drag reduction and the minimum boat-tail area. An optimum boat-tail angle (in the range of 15 degrees) is identified for 0 degrees yaw from both experimental and numerical data. For boat-tail angles greater than optimum a distinct increase in drag is observed in the experimental data, which is associated with flow separation. Comparison of experimental and numerical results show reasonable agreement for attached flow cases, and indicate a similar optimal boat-tail angle.
Unsteady Aerodynamics Simulation of a Heavy-Duty Truck in Wind Gusts Coupled With Vehicle Motion Analysis in Six Degrees of Freedom
Authors: Nakashima Takuji , Tsubokura Makoto , Matsuda Syumei , Doi Yasuaki
Published: June 2012

A one-way coupled analysis was used to investigate both the unsteady aerodynamic forces on a simplified heavy-duty truck in strong wind gusts and their effects on its motion. The vehicle model for the dynamics simulation was extended to six degrees of freedom (6DoF). First, a transitional aerodynamics simulation was conducted for the simplified truck with a fixed vehicle attitude but subject to a sudden crosswind. Based on the visualized results of this aerodynamics simulation, flow phenomena generating transitional aerodynamic forces and moments are discussed, especially those acting in the vertical direction. While the truck was running into the crosswind region, the growth and breakdown of a large-scale vortex above the container generated a transitional behavior of aerodynamic lift and pitching moment. Next, time series of the six components of the aerodynamic forces and moments were input into the vehicle dynamics simulation. By comparing the results with those of a quasi-steady aerodynamics simulation, the effect of transitional aerodynamics on vertical motions was clarified, with the largest difference found in a rolling motion. Moreover, the effect of considering 6DoF was investigated by also conducting the vehicle dynamics simulation with 3DoF. The consideration of dynamics in the vertical direction changed the estimation of tire forces, which were related to a vertical load on the tire. Finally, the effects of considering 6DoF were also identified for horizontal motions.
Jet Flow Control by DBD Plasma Actuator: Effect of Electrode Dimensions on Jet Diffusion
Authors: Jin Hongyu , Ono Takashi , Kimura Motoaki
Published: June 2012

Dielectric barrier discharge (DBD) plasma actuators have been investigated by many researchers as flow-control devices. In the present study, we attempt to apply such actuators to a jet flow. In order to achieve enhanced mixing in a jet flow, we focused on the voltage and the frequency of the plasma actuator to examine their effect on the velocity and turbulence of the jet flow. This time, we examined how the induced flow by the plasma actuator electrode dimensions occurred. It was expected that higher velocity would have a larger effect on the jet flow in last year. In this study, we measured the flow velocity for different voltages and frequencies, and determined the most effective conditions for generating the induced flow. We apply that DBD plasma actuators to enhance turbulent intensity and jet flow’s diffusion.
Numerical Simulation of Mixing Enhancement and Suppression in Two-Dimensional Mixing Layer
Authors: Kawagoe Masayuki , Fukagata Koji
Published: June 2012

Direct numerical simulation of two-dimensional mixing layer with time-periodic forcing mimicking the input of piezofilm actuator is performed. Three different forcing frequencies (i.e., the natural frequency, its first subharmonic and second subharmonic frequencies) are examined. Simplified chemical reactions are also taken into account. We investigate whether mixing is promoted or suppressed using two indices: the momentum thickness and the concentration of chemical product. The momentum thickness indicates that the forcing enhances the development of mixing layer near the inlet and suppresses it in the region right downstream. Instantaneous vorticity fields show that the location where the vortex pairing starts depend on the forcing frequency. The effect of forcing on the mixing layer development strongly depends on its frequency: in particular, the forcing at the second subharmonic frequency is found to suppress the development of mixing layer in a wide region. On the other hand, from the chemical product concentration, mixing is found to be promoted regardless of the forcing frequency. We also investigate how far the control effect lasts. It is revealed that in the downstream region the mixing layer thickness develops linearly regardless of the forcing frequency, which in turn suggests that the present numerical simulation is performed in a computational domain large enough to examine the control effect.
Numerical Study on the Flow Past a Twisted Elliptic Cylinder With Subcritical Reynolds Number
Authors: Kim Min Ho , Lee Jin Woog , Yoon Hyun Sik , Ha Man Yeong
Published: June 2012

Large eddy simulation of flow past a torsional cylinder has been carried out at a Reynolds number of 3900 based on the cylinder diameter and the free stream velocity using finite volume method. The torsional cylinder has been formed by rotating the elliptic cross sectional area along the spanwise direction. For an ellipse, different eccentricities are considered to observe the effect of eccentricity on the flow fields. The excellent comparisons with previous studies for the cases of a smooth cylinder and a wavy cylinder having sinusoidal variation in cross sectional area along the spanwise direction guarantee the accuracy of present numerical methods. The effect of eccentricity on the drag and lift coefficients representing the fluid flow characteristics has been investigated by comparing with those of the smooth cylinder, resulting in enhancement of drag reduction and suppression of vortex-induced vibration. The isosurface of swirling strength has been adopted to identify the vortical structures in the turbulent wake.
Effect of Development-Zone Restrictions on the Turbulent Characteristics of Impinging Jet Flow
Authors: Kawaguchi Takefumi , Shekhar Chandra , Nishino Koichi
Published: June 2012

This study is to examine the turbulent characteristics of an axisymmetric impinging jet flow in the stagnation region. The flow measurement is carried out using a standard PIV technique. The changes of the turbulent characteristics of the jet with various levels of the development-zone restriction are examined. The restrictions are imposed by putting an annular, concentric, solid block around the jet, and then varying its inner diameter. The PIV measurement of the flow field is carried out for each case. The height of the block is kept constant for all the cases, with the Reynolds number of 5000, which falls well within the turbulent range. The instantaneous velocity data obtained from the PIV measurement is used to calculate the turbulent statistics. The results are compared for all of the cases. In consequence, it is found that the turbulent statistics do not change much for the block’s inner diameter larger than a critical value, which is found to be three times the inlet diameter of the jet. However, if it is smaller, the turbulent statistics vary significantly, as the inner wall of the block damages the development of the potential core of the jet.
The Development of Extremely-Compact Static Pressure Probe for the Simultaneous Measurement of Pressure and Velocity in the Turbulent Flows
Authors: Onishi Kazuhiro , Terashima Osamu , Sakai Yasuhiko , Nagata Kouji
Published: June 2012

A new static pressure probe was developed to improve the space resolution and the measurement accuracy of the combined probe for the simultaneous measurement of the static pressure and the velocity in turbulent flows. The external diameter of the static pressure tube is 0.3 mm and its internal diameter is 0.2 mm. There are 8 static pressure holes on the wall of the static pressure tube and their diameters are 0.1 mm. The MEMS microphone is used as the pressure sensor and embedded inside the flare of the static pressure tube. The diameter of the MEMS microphone is 2.54 mm and has the wide range flat frequency response. The measurement results by the new static pressure probe in the two-dimensional turbulent jet show that the measurement accuracy of the static pressure probe is sufficient and the seven-thirds power law is clearly observed in the power spectra of the fluctuating pressure measured at the position of a half width of the mean velocity distribution in the cross-streamwise direction apart from the jet center line. In addition, the yaw angle characteristics of this new pressure probe shows that the measurement accuracy of the static pressure has less dependency on the yaw angle of the probe to the flow direction than the one of the previous static pressure tube (its external diameter is 0.5 mm). From these results, it is found that the new static pressure probe is effective for the measurement of static pressure in turbulent flows and useful to improve the space resolution and the measurement accuracy of the combined probe for the simultaneous measurement of the velocity and the static pressure. By using this static pressure tube, the space resolution of the combined probe is reduced approximately 40%. Further, by combing two X-type hot-wire probes with the new pressure probe, the simultaneous measurement of three velocity components and static pressure is realized.
A Multi-Parametric Particle Pairing Algorithm for Particle Tracking Velocimetry in Single and Multiphase Flows
Authors: Cardwell Nicholas D. , Vlachos Pavlos P.
Published: June 2012

The measurement of turbulent flows becomes problematic when considering a dispersed multiphase flow, which typically requires special techniques focusing on the simultaneous resolution of both the carrier and discrete phases present in the flowfield. The method presented in this paper, a multi-parametric particle pairing algorithm for particle tracking velocimetry (MP3-PTV), provides a powerful and flexible technique for the measurement of multiphase flows. Combined with a traditional Particle Image Velocimetry (PIV) system, the MP3-PTV employs a variable pair-matching algorithm which utilizes displacement preconditioning in combination with estimated particle size and intensity to match particle pairs between successive images. To improve the method’s efficiency, a new particle identification and segmentation routine was also developed. Validation of the new method was performed on two artificial data sets: a traditional single-phase flow published by the Visualization Society of Japan (VSJ) and an in-house generated multiphase flow having a bi-modal distribution of particles diameters. On the VSJ data set, the newly presented segmentation routine delivered a two-fold increase in identifying particles compared to other published methods. For the simulated multiphase flow data set, measurement efficiency of the dispersed phase improved from 9% to 41% for MP3-PTV as compared to traditional hybrid PTV.
Wet Steam Flowrate Calibration Facility
Authors: Ishibashi Masahiro , Funaki Tatsuya , Takamoto Masaki , Umezawa Shuichi , Sakai Masayuki , Amari Haruo , Shimada Hiroyuki , Morita Ryo , Inada Fumio , Uchiyama Yuta
Published: June 2012

Newly developed wet steam flowrate calibration facility is introduced. It has a closed loop in which boilers generate a steam flow up to 800 kg/h. Steam flow of known wetness up to 12% is generated by cooling down a dry steam flow by a heat exchanger. The wetness is calculated from the enthalpy the heat exchanger draws from the dry steam flow. Analysis of the facility performance, calibration results of an orifice flowmeter calibration, and uncertainty analysis are described.
A Molecular Dynamics Approach for Nucleation-Growth of Cryogenic Cavitation
Authors: Tsuda Shin-ichi , Komatsu Taiga , Takagi Shu , Matsumoto Yoichiro
Published: June 2012

The growth of cavitation bubble nuclei in a metastable state in liquid argon, as one of cryogenic fluids, was investigated using a Molecular Dynamics (MD) simulation with a Nose´-Hoover chain thermostat. We observed rapid growth of bubble nuclei with weak inter-bubble interaction in the early stage, while observed a competing coarsening that looks like Ostwald ripening in the late stage and its growth exponent n became 0.51. We compared the present MD result with that in an adiabatic simulation (Energy-constant MD without any thermostats), and the influence of the field temperature was discussed. Also, we compared the present MD results with a coarsening theory for droplets, and discussed the characteristics of the coarsening mechanism of bubble nuclei.
DEM Simulation for Specific Gravity Separation of Plastic Particles Using Air-Table
Authors: Tsunazawa Yuki , Wang Tingwei , Torige Kenichiro , Tokoro Chiharu
Published: June 2012

Air-table is one of the specific gravity separators which have been expected as an effective dry separator for waste products such as plastic or glass. The objective of this study is an application of DEM to describe the basic behavior of plastic particles in an air-table separation. The mechanism of particles separation on the table has not been well-known because air-table contains many instrument parameters such as slope and shape of the table, height of the riffle, angle, amplitude and frequency of vibration and wind velocity. In this study, two types of particles which have same diameter and different density were simulated and 3 dimensional position and velocity of them were investigated in the various conditions of instrumental parameters. DEM simulation results showed that the riffle on the table play an important role for the particles separation.
Dynamics of Elliptic Magnetic Particles in Simple Shear Flow
Authors: Kang Tae Gon , Hulsen Martien A. , den Toonder Jaap M. J.
Published: June 2012

A two-dimensional direct simulation method, based on the Maxwell stress tensor and a fictitious domain method, has been employed to investigate the dynamics of elliptic paramagnetic particles suspended in a non-magnetic incompressible Newtonian fluid. A single-particle problem is chosen to investigate the rotational behavior of the particle in the presence of both shear flow and a uniform magnetic field applied externally. The dynamic of the elliptic particle is found to be significantly affected by a dimensionless number called the Mason number, the ratio of the viscous force to the magnetic force acting on the particle. We found a critical Mason number separating two regimes with different particle dynamics. Below the critical number the particle reaches an equilibrium position after finite rotation. Above the critical number, however, the particle rotates continuously. As for the multi-particle problem in the presence of an external field and imposed shear flow, three regimes of the Mason number were found, showing different topology of the chain of particles and fluid flow due to the combined effect of the magnet and viscous forces.
Size-Exclusion Surface Plasmon Resonance Sensing With a Microslit Array Chip
Authors: Nagase Noriko , Shimizu Kazunori , Miyanishi Nobumitsu , Shimamoto Seiko , Terao Kyohei , Suzuki Takaaki , Oohira Fumikazu
Published: June 2012

In this study, we propose a novel surface plasmon resonance (SPR) chip on which the microslit array was fabricated. The microslit excludes micrometer-size objects that are larger than its slit size from sensing field, so that it acts as a filter. In order to confirm the filtereffect, we demonstrated the sensing of microparticles of different diameters using the SPR chip. As the demonstration of the biotechnology application, we performed the discrimination of aggregation of bio-molecules using SGNP (Sugar chain imobilized Gold Nano Particle) as a model sample.
A Molecular Dynamics Study for the Characteristics of Proton Transfer in Polymer Electrolyte Membrane
Authors: Tokumasu Takashi , Yoshida Taiki
Published: June 2012

These days Polymer Electrolyte Fuel Cell (PEFC) is the most developed fuel cell. A polymer electrolyte membrane (PEM) is used in PEFC. Its efficiency is proportional to the proton transferring efficiency, which depends on the nanoscale structure of water. In this study, the property of proton transfer was analyzed by Molecular Dynamics (MD) method including Grotthus mechanism by Empirical Valence Bond (EVB) method. Nafion membrane was adopted as PEM. The potential energy barrier of proton hopping obtained by EVB method was adjusted to reproduce the energy barrier obtained by Density Functional Theory (DFT). In MD simulation, the distribution of water in Nafion was firstly analyzed. The results showed that liquid molecules gather around sulfo groups. Next, the property of proton transfer was analyzed by Mean Square Displacement (MSD).
Application of Micro-Schlieren Technique to Quantitative Analysis of Mass Transport in a Micromixer
Authors: Hsiao Tzu-hsun , Sun Chen-li
Published: June 2012

In this study, we develop a micro-schlieren analysis methodology to facilitate measurement of inhomogeneities in a micromixer. As a first step, calibration procedures are performed by mixing dilute aqueous methanol and water in a T-microchannel in order to obtain the relation between the refractive index gradients and pixel grayscale values. Knowing the influences of concentration in the refractive index of aqueous methanol solution, we are able to associate pixel grayscale values with the concentration gradient along the cross-stream axis. For refractive index gradient larger than 130 m−1, the calibration curve shows great linearity, setting the sensitivity limit of our quantitative micro-schlieren system to 2 × 104 m−1 for concentration gradient. We then implement this methodology to examine the mixing behavior in a microfluidic oscillator. The results prove that the micro-schlieren technique is able to provide spatially-resolved, noninvasive, full-field transient measurements and offer a valuable insight into the microscale mass transport phenomena that other methods fail to deliver. While the micro-schlieren technique is directly linked to the measurement of refractive index gradient, the present methodology can be extended to other scalar quantitations that are related to the variation of refractive index in the future.
Theoretical Development of Predicted Iteration Method for Considering Electron Dynamics in Quantum Molecular Dynamics
Authors: Doi Kentaro , Kawano Satoyuki
Published: June 2012

In the present study, a theoretical principle of molecular dynamics methods is developed, in which electron transfers are taken into account effectively based on quantum mechanics. In chemical reaction systems, electrodynamics should be considered in the molecular dynamics simulation because electron transfers play an important role. In this study, an effective procedure is proposed to treat time evolutions of electronic wavefunctions. In the procedure, electronic wavefunctions can be transformed to other spaces such as Mulliken atomic charges or electrostatic potentials, and then their time evolutions are coupled with the motions of ionic cores. The present method is applied to some chemical reaction systems, and charge transfer effects can be treated successfully in molecular dynamics simulations. The importance of a coupling method of molecular dynamics and electrodynamics is described.
Electronic effects of Cd on the formation of the CdS/CuInS2 heterojunction
Authors: Johnson Benjamin , Klaer Jo , Vollmer Antje , Lauermann Iver
Published: June 2012

The possibility of doping and Fermi level pinning of CuInS2 thin layer solar cell absorbers caused by the diffusion of Cd into the absorber during junction formation via chemical bath deposition was investigated. The analysis of thin CdS layers deposited on CuInS2 showed the amount of deposition-induced band bending on the CuInS2 surface (position of the Fermi level in the respective bandgaps) was not experimentally reproducible. However, the value of the valence band offset between the two materials was reproducible between different depositions within the error of the measurement. Thus, the deposition of the CdS does not lead to a consistent pinning position of the Fermi level in the CuInS2/CdS heterojunction. The removal of the CdS layers with HCl left a thin Cd-containing layer on the CuInS2 surface and it was shown that this surface was not doped by the remaining Cd. Furthermore, the influence of the HCl of the CuInS2 was explored and found to form a reproducible surface richer in Cu than CuInS2 etched in potassium cyanide solution.
Emittance measurements of electron beams from diamond field emitter arrays
Authors: Jarvis Jonathan D. , Choi Bo K. , Hmelo Anthony B. , Ivanov Borislav , Brau Charles A.
Published: June 2012

Electron injector technology is presently dominated by a variety of photo- and thermionic electron injectors. Although new electron injectors based on field emission appear promising, their success is predicated on the development of reliable, high current density, low emittance, and spatially uniform, field emitter array cathodes. The authors report recent results of transverse-emittance measurements on a particularly promising cathode, the diamond field emitter array. A simple pepperpot technique is used to measure the divergence of the beam emitted from one such cathode at low current density. Based on these measurements, a 1 mm diameter uniformly emitting cathode will have a normalized transverse emittance of ∼1 mm mrad. Our results suggest that the beam quality of these cathodes is satisfactory for use in a variety of applications.
Cooling effect of nanoscale Bi2Te3/Sb2Te3 multilayered thermoelectric thin films
Authors: Hines Mardecial , Lenhardt Joshua , Lu Ming , Jiang Li , Xiao Zhigang
Published: June 2012

Managing high heat flux is one of the greatest technical challenges the integrated circuit (IC) industry is facing because the rising temperature limits device minimization and decreases its lifetime. In this paper, we report the characterization of the cooling effect of nanoscale Bi2Te3/Sb2Te3 multilayered thin films. The multilayer thin film was prepared with e-beam evaporation, and had 21 layers (5-nm-thick each layer and 105-nm-thick total). A thermoelectric device of the multilayer film, which is sandwiched between a diode temperature sensor and a platinum temperature sensor, was fabricated to measure the cooling effect. A maximum cooling temperature difference of about 3 K was obtained from the film at an applied dc electrical current of 5 mA. The nanoscale multilayer film could be integrated in the IC devices for the application of high-efficiency thermoelectric solid-state cooling.
CuOx/CeO2 Nanocomposites Prepared by Deposition-Precipitation: An XPS Study
Authors: Galenda Alessandro , Natile Marta Maria , Glisenti Antonella
Published: June 2012

Copper oxide/Ceria nanocomposite powders were prepared by a deposition-precipitation procedure. The supporting nanosized ceria was obtained by precipitation at 273 K (in presence of H2O2). The samples are characterized by a nominal (i.e. calculated from the weighted amount of precursors) Cu/Ce wt. ratio of 2% (Accession #1152: CuCe2) and 7% (Accession #1153: CuCe7). The surface properties and the influence of the Cu/Ce atomic ratio were investigated by means of XPS (using a standard Al Kα source). Besides the wide scan spectra, detailed spectra for the Ce 3d, Ce 4d, Cu 2p and O 1s regions and related data are presented and discussed. XP analysis reveals the presence of copper oxide (Cu2O is observed in the sample with lower Cu/Ce wt. ratio whereas CuO is prevalent in the sample richer in Cu). In both the samples, the surface Cu/Ce atomic ratio obtained from XPS data is rather similar: 0.13 (= 0.06 Cu/Ce wt ratio).
Preexisting BCG-Specific T Cells Improve Intravesical Immunotherapy for Bladder Cancer
Authors: Biot Claire , Rentsch Cyrill A. , Gsponer Joel R. , Birkhäuser Frédéric D. , Jusforgues-Saklani Hélène , Lemaître Fabrice , Auriau Charlotte , Bachmann Alexander , Bousso Philippe , Demangel Caroline , Peduto Lucie , Thalmann George N. , Albert Matthew L.
Published: June 2012

Preexisting immunity to BCG improves treatment response to intravesical BCG therapy for bladder cancer in mouse models and humans.
Therapeutic Modulation of Microbiota-Host Metabolic Interactions
Authors: Holmes Elaine , Kinross James , Gibson Glenn R. , Burcelin Remy , Jia Wei , Pettersson Sven , Nicholson Jeremy K.
Published: June 2012

Abnormal microbial-host metabolic interactions underlying disease provide new targets for therapeutic intervention.
Casting a Wide NET for TRALI
Authors: Tanhehco Yvette
Published: June 2012

Neutrophil extracellular traps formed during lung injury contribute to disease development and provide targets for specific therapy.
Variations of AbaR4-Type Resistance Islands in Acinetobacter baumannii Isolates from South Korea
Authors: Kim Dae Hun , Park Young Kyoung , Ko Kwan Soo
Published: June 2012

AbaR resistance islands in
Acinetobacter baumannii
isolates from South Korea were investigated. AbaR4-type resistance islands, including
bla
OXA-23
-containing Tn
2006
, interrupted the
comM
gene in
A. baumannii
ST75 isolates. However, Tn
2006
was not identified within AbaR resistance islands of ST138 isolates, although the
bla
OXA-23
gene was detected in them. The similar structures of resistance islands suggest that most carbapenem-resistant
A. baumannii
isolates in South Korea have originated from the same ancestor with a globally disseminated clone, GC II.
Insightful practice: a reliable measure for medical revalidation
Authors: Murphy Douglas J , Guthrie Bruce , Sullivan Frank M , Mercer Stewart W , Russell Andrew , Bruce David A
Published: June 2012

Background

Medical revalidation decisions need to be reliable if they are to reassure on the quality and safety of professional practice. This study tested an innovative method in which general practitioners (GPs) were assessed on their reflection and response to a set of externally specified feedback.

Setting and participants

60 GPs and 12 GP appraisers in the Tayside region of Scotland, UK.

Methods

A feedback dataset was specified as (1) GP-specific data collected by GPs themselves (patient and colleague opinion; open book self-evaluated knowledge test; complaints) and (2) Externally collected practice-level data provided to GPs (clinical quality and prescribing safety). GPs' perceptions of whether the feedback covered UK General Medical Council specified attributes of a ‘good doctor’ were examined using a mapping exercise. GPs' professionalism was examined in terms of appraiser assessment of GPs' level ofinsightful practice, defined as: engagement with, insight into and appropriate action on feedback data. The reliability of assessment ofinsightful practiceand subsequent recommendations on GPs' revalidation by face-to-face and anonymous assessors were investigated using Generalisability G-theory.

Main outcome measures

Coverage of General Medical Council attributes by specified feedback and reliability of assessor recommendations on doctors' suitability for revalidation.

Results

Face-to-face assessment proved unreliable. Anonymous global assessment by three appraisers ofinsightful practicewas highly reliable (G=0.85), as were revalidation decisions using four anonymous assessors (G=0.83).

Conclusions

Unlike face-to-face appraisal, anonymous assessment ofinsightful practiceoffers a valid and reliable method to decide GP revalidation. Further validity studies are needed.
Expression and morphology of enterotoxigenicEscherichia colisurface antigen CS31A inE. coliK12 andVibrio cholerae
Authors: Kuehni-Boghenbor Kathrin , Jordi Helene A. , Frey Joachim , Vilei Edy M. , Favre Didier , Stoffel Michael H.
Published: June 2012

Enterotoxigenic Escherichia coli (ETEC) is known as a worldwide cause of diarrheal disease. The pathogenesis involves the attachment of the microorganisms to the mucosa and the production of enterotoxins. Surface expression of CS31A fimbriae was assessed by Western blots, dot blots, immunofluorescence, and electron microscopy using negative staining and immunogold labeling. These investigations revealed significant differences in both the morphology of the wild-type and recombinant strains and the antigen exposure of CS31A in the wild-type and recombinant strains. In the wild-type ETEC strain, expression of CS31A was subject to phase variation. The recombinant E. coli strain produced CS31A but was prone to epitope shedding. In Vibrio cholerae vaccine strain CVD 103-HgR, the recombinant CS31A antigen was expressed but was only found intracellularly. Thus, E. coli strains seem to lend themselves better to the development of recombinant vaccines expressing ETEC-specific antigens at the cell’s surface than strains from other orders or genera such as V. cholerae.
Genetic diversity amongCurtobacterium flaccumfacienspv.flaccumfacienspopulations in the American High Plains
Authors: Agarkova I.V. , Lambrecht P.A. , Vidaver A.K. , Harveson R.M.
Published: June 2012

Curtobacterium flaccumfaciens pv. flaccumfaciens is a Gram-positive bacterium and has reemerged as an incitant of bacterial wilt in common (dry, edible) beans in western Nebraska, eastern Colorado, and southeastern Wyoming. Curtobacterium flaccumfaciens pv. flaccumfaciens is diverse phenotypically and genotypically and is represented by several different pathogen color variants. The population structure of 67 strains collected between 1957 and 2009, including some isolated from alternate hosts, was determined with 3 molecular typing techniques: amplified fragment length polymorphism (AFLP), repetitive extragenic palindromic polymerase chain reaction (rep-PCR), and pulsed-field gel electrophoresis (PFGE). All 3 typing techniques showed a great degree of population heterogeneity, but they were not congruent in cluster analysis of the C. flaccumfaciens pv. flaccumfaciens populations. Cluster analysis of a composite data set (AFLP, PFGE, and rep-PCR) using averages from all experiments yielded 2 distinct groups: cluster A included strains with colonies of yellow, orange, and pink pigments, and cluster B had strains of only yellow pigment. Strains producing purple extracellular pigment were assigned to both clusters. Thus, C. flaccumfaciens pv. flaccumfaciens is diverse phenotypically and genotypically.
LOGAMEDIATE INFLATION ON THE BRANE
Authors: HERRERA RAMÓN , OLIVARES MARCO
Published: June 2012

Brane inflationary universe model in the context of logamediate inflation is studied. As the energy density we consider two different fields, first a standard scalar field, and then a tachyon field. In the high-energy limit we describes the conditions for theses models. The parameters of our models are constrained from the observational data.
ALTERNATIVE MODELS OF NEUTRON–ANTINEUTRON CONVERSION IN NUCLEI
Authors: NAZARUK V. I.
Published: June 2012

The models of the [Formula: see text] transition in medium and nuclei based on the diagram technique for direct reactions, potential description of [Formula: see text]-medium interaction and field-theoretical approach are considered. It is shown that for the [Formula: see text] transition in medium field-theoretical approach should be used. The lower limit on the free-space [Formula: see text] oscillation time τ is in the range: 1016 yr >τ>1.2⋅109 s .
HUMAN ACTIVITY RECOGNITION BY FUSING MULTIPLE SENSOR NODES IN THE WEARABLE SENSOR SYSTEMS
Authors: GUO YONGCAI , HE WEIHUA , GAO CHAO
Published: June 2012

This paper presents a novel method for recognizing human daily activity by fusion multiple sensor nodes in the wearable sensor systems. The procedure of this method is as follows: firstly, features are extracted from each sensor node and subsequently reduced in dimension by generalized discriminant analysis (GDA), to ensure the real-time performance of activity recognition; then, the reduced features are classified with the multiclass relevance vector machines (RVM); finally, the individual classification results are fused at the decision level, in consideration that the different sensor nodes can provide heterogeneous and complementary information about human activity. Extensive experiments have been carried out on Wearable Action Recognition Database (WARD). Experimental results show that if all the five sensor nodes are fused with the adaptive weighted logarithmic opinion pools (WLOGP) fusion rule, we can even achieve a recognition rate as high as 98.78%, which is far more better than the situations where only single sensor node is available or the activity data is processed by state-of-the-art methods. Moreover, this proposed method is flexible to extension, and can provide a guideline for the construction of the minimum desirable system.
THE EFFECT OF ASYMMETRY AND AXIAL PRESTRAINING ON THE AMPLITUDE OF MECHANICAL STRESSES IN ABDOMINAL AORTIC ANEURYSM
Authors: VELJKOVIĆ DEJAN , FILIPOVIĆ NENAD , KOJIĆ MILOŠ
Published: June 2012

In this work we study the effect of asymmetry and axial prestraining on the maximum effective mechanical stress in relatively small human abdominal aortic aneurysm (AAA) during a cardiac cycle. Our model is based on the fluid-structure interaction (FSI) methodology. The arterial wall is modeled using large strain and large deformation formulation, with hyperelastic material behavior, and isotropic nonlinear strain energy function (SEF) fitted to the averaged data set of biaxial tests of AAA tissue specimens. The results confirm that the magnitude of the maximum von Mises stress increases significantly with asymmetry and decreases with aneurysmal length. It is found that the amplitude in variation of the maximum effective stress changes in the same manner as the maximum stress. These results indicate that a short asymmetric AAA is under significant dynamic stress, which might be one of the important factors in a progressive AAA growth over time. It is also found that, in most considered cases, magnitude and amplitude of the maximum effective stress of an AAA is smaller when the artery is pre-stretched in axial direction, while a pre-stretched artery with aneurysm has slightly larger relative volume change of lumen during cardiac cycle than the unstretched AAA.
COMPLEX TEMPORAL STRUCTURE OF ACTIVITY IN ON-LINE ELECTRONIC AUCTIONS
Authors: SLANINA FRANTIŠEK
Published: June 2012

We analyze empirical data from the internet auction site Aukro.cz. The time series of activity shows truncated fractal structure on scales from about 1 min to about 1 day. The distribution of waiting times as well as the distribution of number of auctions within fixed interval is a power law, with exponents 1.5 and 3, respectively. Possible implications for the modeling of stock-market fluctuations are briefly discussed.
Synthesis of a cofacial chlorin dimer of defined symmetry
Authors: Thanh Nguyen Thi Viet , Könekamp Thorsten , Hanke Daniela , Löwer Franziska , Borrmann Tobias , Montforts Franz-Peter
Published: June 2012

Special pair chlorophylls arranged in a cofacial dimeric structure play an important role in the initial step of light induced electron transfer of photosynthetic reaction centers of bacteria and plants. For mimicking the natural photosynthetic reaction center we aimed on synthesis of an artificial special pair 13 constructed from two chlorin subunits 5a, b and a rigid biphenylene spacer moiety 11. Due to the reduced C2h symmetry of the chlorin units compared with so far used D4h porphyrins and due to the rigid spacer a cofacial dimer of defined symmetry and distance was obtained.
Geometry of the Faces for Separable States Arising from Generalized Choi Maps
Authors: Ha Kil-Chan , Kye Seung-Hyeok
Published: June 2012

We exhibit examples of separable states which are on the boundary of the convex cone generated by all separable states but in the interior of the convex cone generated by all PPT states. We also analyze the geometric structures of the smallest face generated by those examples. As a byproduct, we obtain a large class of entangled states with positive partial transposes.
Galois Actions on the Eigenproblem of the Heisenberg Heptagon
Authors: Milewski Jan , Banaszak Grzegorz , Lulek Tadeusz , Łabuz Mirosław , Stagraczyński Ryszard
Published: June 2012

We analyse the exact solution of the eigenproblem for the Heisenberg Hamiltonian of magnetic heptagon, i.e. the ring of N = 7 nodes, each with spin 1/2, within the XXX model with nearest neighbour interactions, from the point of view of finite extensions of the field ℚ of rationals. We point out, as the main result, that the associated arithmetic structure of these extensions makes natural an introduction of some Galois qubits. They are two-dimensional subspaces of the Hilbert space of the model, which admit a quantum informatic interpretation as elementary memory units for a (hypothetical) computer, based on their distinctive properties with respect to the action of related Galois group for indecomposable factors of the secular determinant. These Galois qubits are nested on the lattice of subfields which involves several minimal fields for determination of eigenstates (the complex Heisenberg field), spectrum (the real Heisenberg field), and Fourier transforms of magnetic configurations (the cyclotomic field, based on the simple 7th root of unity). The structure of the corresponding lattice of Galois groups is presented in terms of Kummer theory, and its physical interpretation is indicated in terms of appropriate permutations of eigenstates, energies, and density matrices.
Introduction to the special issue on affective interaction in natural environments
Authors: Castellano Ginevra , Riek Laurel D. , Peters Christopher , Karpouzis Kostas , Martin Jean-Claude , Morency Louis-Philippe
Published: June 2012

Affect-sensitive systems such as social robots and virtual agents are increasingly being investigated in real-world settings. In order to work effectively in natural environments, these systems require the ability to infer the affective and mental states of humans and to provide appropriate timely output that helps to sustain long-term interactions. This special issue, which appears in two parts, includes articles on the design of socio-emotional behaviors and expressions in robots and virtual agents and on computational approaches for the automatic recognition of social signals and affective states.
Rebuild processing in RAID5 with emphasis on the supplementary parity augmentation method[37]
Authors: Thomasian Alexander
Published: June 2012

The rotated parity RAID5 disk array tolerates single disk failures by continuing operation by on-demand reconstruction of data blocks of the failed disk, until the systematic reconstruction of the contents of the failed disk is completed by the rebuild process on a spare disk. Supplementary Parity Augmentation (SPA), unlike the pyramid code, which has two parities covering half of the arrays disks each, extends RAID5's P parity with an additional S parity, which covers half of the disks. The extra load with respect to RAID5 of updating the S parity by one half of the disks is compensated by the more efficient on demand reconstructtion and rebuild processing when a disk fails. Although SPA has the same disk space redundancy level as RAID6, unlike RAID6 it can only deal with roughly half of all possible double disk failure cases for eight disks. For rebuild processing SPA reads half of the disks required by RAID5 and this leads to a higher Mean Time to Data Loss than RAID5, since fewer Latent Sector Errors are encountered. We review performance and reliability modeling of RAID5 arrays to provide insights into SPA's performance and reliability, which cannot be gained from numerical results alone. SPA is outperformed by the Intra-Disk Redundancy schemes combined with RAID5, which results in RAID6's reliability and RAID5 performance.
Anandamide regulates the expression of GnRH1, GnRH2, and GnRH-Rs in frog testis
Authors: Chianese Rosanna , Ciaramella Vincenza , Scarpa Donatella , Fasano Silvia , Pierantoni Riccardo , Meccariello Rosaria
Published: June 2012

Gonadotropin-releasing hormone (either GnRH1 or GnRH2) exerts a local activity in vertebrate testis, including human testis. Relationships between endocannabinoid (eCB) and GnRH systems in gonads have never been elucidated in any species so far. To reveal a cross-talk between eCBs and GnRH at testicular level, we characterized the expression of GnRH ( GnRH1 and GnRH2) as well as GnRH receptor ( GnRH-R1, -R2, and -R3) mRNA in the testis of the anuran amphibian Rana esculenta during the annual sexual cycle; furthermore, the corresponding transcripts were localized inside the testis by in situ hybridization. The possible endogenous production of the eCB, anandamide (AEA), was investigated in testis by analyzing the expression of its biosynthetic enzyme, Nape-pld. Incubations of testis pieces with AEA were carried out in the postreproductive period (June) and in February, when a new spermatogenetic wave takes place. In June, AEA treatment significantly decreased GnRH1 and GnRH-R2 mRNA, stimulated the transcription of GnRH2 and GnRH-R1, and did not affect GnRH-R3 expression. In February, AEA treatment upregulated GnRH2 and GnRH-R3 mRNA, downregulated GnRH-R2, and did not affect GnRH1 and GnRH-R1 expression. These effects were mediated by type 1 cannabinoid receptor ( CB1) since they were fully counteracted by SR141716A (Rimonabant), a selective CB1 antagonist. In conclusion, eCB system modulates GnRH activity in frog testis during the annual sexual cycle in a stage-dependent fashion.
Logistic model of glucose-regulated C-peptide secretion: hysteresis pathway disruption in impaired fasting glycemia
Authors: Keenan Daniel M. , Basu Rita , Liu Yan , Basu Ananda , Bock Gerlies , Veldhuis Johannes D.
Published: June 2012

The present analysis tests the hypothesis that quantifiable disruption of the glucose-stimulated insulin-secretion dose-response pathway mediates impaired fasting glycemia (IFG) and type 2 diabetes mellitus (DM). To this end, adults with normal and impaired fasting glycemia (NFG, n = 30), IFG ( n = 32), and DM ( n = 14) were given a mixed meal containing 75 g glucose. C-peptide and glucose were measured over 4 h, 13 times in NFG and IFG and 16 times in DM (age range 50–57 yr, body mass index 28–32 kg/m2). Wavelet-based deconvolution analysis was used to estimate time-varying C-peptide secretion rates. Logistic dose-response functions were constructed analytically of the sensitivity, potency, and efficacy (in the pharmacological sense of slope, one-half maximal stimulation, and maximal effect) of glucose's stimulation of prehepatic insulin (C-peptide) secretion. A hysteresis changepoint time, demarcating unequal glucose potencies for onset and recovery pathways, was estimated simultaneously. According to this methodology, NFG subjects exhibited distinct onset and recovery potencies of glucose in stimulating C-peptide secretion (6.5 and 8.5 mM), thereby defining in vivo hysteresis (potency shift −2.0 mM). IFG patients manifested reduced glucose onset potency (8.6 mM), and diminished C-peptide hysteretic shift (−0.80 mM). DM patients had markedly decreased glucose potency (18.8 mM), reversal of C-peptide's hysteretic shift (+4.5 mM), and 30% lower C-peptide sensitivity to glucose stimulation. From these data, we conclude that a dynamic dose-response model of glucose-dependent control of C-peptide secretion can identify disruption of in vivo hysteresis in patients with IFG and DM. Pathway-defined analytic models of this kind may aid in the search for prediabetes biomarkers.
A fluorogenic near-infrared imaging agent for quantifying plasma and local tissue renin activity in vivo and ex vivo
Authors: Zhang Jun , Preda Dorin V. , Vasquez Kristine O. , Morin Jeff , Delaney Jeannine , Bao Bagna , Percival M. David , Xu Daigen , McKay Dan , Klimas Michael , Bednar Bohumil , Sur Cyrille , Gao David Z. , Madden Karen , Yared Wael , Rajopadhye Milind , Peterson Jeffrey D.
Published: June 2012

The renin-angiotensin system (RAS) is well studied for its regulation of blood pressure and fluid homeostasis, as well as for increased activity associated with a variety of diseases and conditions, including cardiovascular disease, diabetes, and kidney disease. The enzyme renin cleaves angiotensinogen to form angiotensin I (ANG I), which is further cleaved by angiotensin-converting enzyme to produce ANG II. Although ANG II is the main effector molecule of the RAS, renin is the rate-limiting enzyme, thus playing a pivotal role in regulating RAS activity in hypertension and organ injury processes. Our objective was to develop a near-infrared fluorescent (NIRF) renin-imaging agent for noninvasive in vivo detection of renin activity as a measure of tissue RAS and in vitro plasma renin activity. We synthesized a renin-activatable agent, ReninSense 680 FAST (ReninSense), using a NIRF-quenched substrate derived from angiotensinogen that is cleaved specifically by purified mouse and rat renin enzymes to generate a fluorescent signal. This agent was assessed in vitro, in vivo, and ex vivo to detect and quantify increases in plasma and kidney renin activity in sodium-sensitive inbred C57BL/6 mice maintained on a low dietary sodium and diuretic regimen. Noninvasive in vivo fluorescence molecular tomographic imaging of the ReninSense signal in the kidney detected increased renin activity in the kidneys of hyperreninemic C57BL/6 mice. The agent also effectively detected renin activity in ex vivo kidneys, kidney tissue sections, and plasma samples. This approach could provide a new tool for assessing disorders linked to altered tissue and plasma renin activity and to monitor the efficacy of therapeutic treatments.
WISE 2005: responses of women to sublingual nitroglycerin before and after 56 days of 6° head-down bed rest
Authors: Zuj K. A. , Edgell H. , Shoemaker J. K. , Custaud M. A. , Arbeille P. , Hughson R. L.
Published: June 2012

This study tested the hypothesis that cardiovascular effects of sublingual nitroglycerin (NG) would be exaggerated after 56 days of 6° head-down bed rest (HDBR) in women, and that an aerobic and resistive exercise countermeasure (EX, n = 8) would reduce the effect compared with HDBR without exercise (CON, n = 7). Middle cerebral artery maximal blood flow velocity (CBFV), cardiac stroke volume (SV), and superficial femoral artery blood flow (Doppler ultrasound) were recorded at baseline rest and for 5 min following 0.3 mg sublingual NG. Post-HDBR, NG caused greater increases in heart rate (HR) in CON compared with EX (+24.9 ± 7.7 and +18.8 ± 6.6 beats/min, respectively, P < 0.0001). The increase in HR combined with reductions in SV to maintain cardiac output. Systolic, mean, and pulse pressures were reduced 5–10 mmHg by NG, but total peripheral resistance was only slightly reduced at 3 min after NG. Reductions in CBFV of −12.5 ± 3.8 cm/s were seen after NG, but a reduction in the Doppler resistance index suggested dilation of the middle cerebral artery with no differences after HDBR. The femoral artery dilated with NG and blood flow was reduced ∼50% with the appearance of large negative waves suggesting a marked increase in downstream resistance, but there were no effects of HDBR. In general, responses of women to NG were not altered by HDBR; the greater increase in HR in CON but not EX was probably a consequence of cardiovascular deconditioning. These results contrast with the hypothesis and a previous investigation of men after HDBR by revealing no change in cardiovascular responses to exogenous nitric oxide.