bluuebunny/crossref_metadata_2025 huggingface dataset:
Swine Influenza Virus and Association with the Porcine Respiratory Disease Complex in Pig Farms in Southern Brazil
Authors: Schmidt C. , Cibulski S. P. , Andrade C. P. , Teixeira T. F. , Varela A. P. M. , Scheffer C. M. , Franco A. C. , de Almeida L. L. , Roehe P. M.
Published: August 2015

Despite the putative endemic status of swine influenza A virus (swIAV) infections, data on the occurrence of swine influenza outbreaks are scarce in Brazil. The aim of this study was to detect and subtype swIAVs from six outbreaks of porcine respiratory disease complex (PRDC) in southern Brazil. Nasal swabs were collected from 66 piglets with signs of respiratory disease in six herds. Lung tissue samples were collected from six necropsied animals. Virus detection was performed by PCR screening and confirmed by virus isolation and hemagglutination (HA). Influenza A subtyping was performed by a real‐time reverse transcriptase PCR (rRT‐PCR) to detect the A(H1N1)pdm09; other swIAV subtypes were determined by multiplex RT‐PCR. In lung tissues, the major bacterial and viral pathogens associated with PRDC (Pasteurella multocida, Mycoplasma hyopneumoniae, Actinobacillus pleuropneumoniae, Haemophilus parasuis and PCV2) were investigated. In some affected pigs, clinico‐pathological evaluations were conducted. Influenza A was detected by screening PCR in 46 of 66 swab samples and from five of six lungs. Virus was recovered from pigs of all six herds. Subtype A(H1N1)pdm09 was detected in four of six herds and H1N2 in the other two herds. In lung tissues, further agents involved in PRDC were detected in all cases; Pasteurella multocida was identified in five of six samples and Mycoplasma hyopneumoniae in three of six. Actinobacillus pleuropneumoniae (1/6), Haemophilus parasuis (1/6) and PCV2 (1/6) were also detected. These findings indicate that subtypes A(H1N1)pdm09 and H1N2 were present in pigs in southern Brazil and were associated with PRDC outbreaks.
Sesamin prevents decline in exercise capacity and impairment of skeletal muscle mitochondrial function in mice with high‐fat diet‐induced diabetes
Authors: Takada Shingo , Kinugawa Shintaro , Matsushima Shouji , Takemoto Daisuke , Furihata Takaaki , Mizushima Wataru , Fukushima Arata , Yokota Takashi , Ono Yoshiko , Shibata Hiroshi , Okita Koichi , Tsutsui Hiroyuki
Published: August 2015

New Findings

What is the central question of this study?

Our aim was to examine whether sesamin can prevent a decline in exercise capacity in high‐fat diet‐induced diabetic mice. Our hypothesis was that maintenance of mitochondrial function and attenuation of oxidative stress in the skeletal muscle would contribute to this result.

What is the main finding and its importance?

The new findings are that sesamin prevents the diabetes‐induced decrease in exercise capacity and impairment of mitochondrial function through the inhibition of NAD(P)H oxidase‐dependent oxidative stress in the skeletal muscle. Sesamin may be useful as a novel agent for the treatment of diabetes mellitus.

We previously reported that exercise capacity and skeletal muscle mitochondrial function in diabetic mice were impaired, in association with the activation of NAD(P)H oxidase. It has been reported that sesamin inhibits NAD(P)H oxidase‐induced superoxide production. Therefore, we examined whether the antioxidant sesamin could prevent a decline in exercise capacity in mice with high‐fat diet (HFD)‐induced diabetes. C57BL/6J mice were fed a normal diet (ND) or HFD, then treated or not with sesamin (0.2%) to yield the following four groups: ND, ND+Sesamin, HFD and HFD+Sesamin (n = 10 each). After 8 weeks, body weight, fat weight, blood glucose, insulin, triglyceride, total cholesterol and fatty acid were significantly increased in HFD compared with ND mice. Sesamin prevented the increases in blood insulin and lipid levels in HFD‐fed mice, but did not affect the plasma glucose. Exercise capacity determined by treadmill tests was significantly reduced in HFD mice, but almost completely recovered in HFD+Sesamin mice. Citrate synthase activity was significantly decreased in the skeletal muscle of HFD mice, and these decreases were also inhibited by sesamin. Superoxide anion and NAD(P)H oxidase activity were significantly increased in HFD mice compared with the ND mice and were ameliorated by sesamin. Sesamin prevented the decline in exercise capacity in HFD‐induced diabetic mice via maintenance of mitochondrial function, fat oxidation and attenuation of oxidative stress in the skeletal muscle. Our data suggest that sesamin may be useful as a novel agent for the treatment of diabetes mellitus.
Experimental Analysis of the Unbalance Response of Rigid Rotors Supported on Aerodynamic Foil Bearings
Authors: Balducchi Franck , Arghir Mihai , Gauthier Romain
Published: August 2015

The paper presents the experimental unbalance response of two slightly different rigid rotors supported by aerodynamic foil bearings. Impulse (Pelton) turbines manufactured directly in the mass of the rotors (on the outer surface) entrain both rotors at rotation speeds comprised between 50 krpm and 100 krpm. The displacements in the two foil bearings are measured during coast down and are depicted as waterfall plots. They show typical nonlinear behavior, i.e., subsynchronous vibrations accompanying the synchronous component. The measurements clearly show that the subsynchronous components bifurcate or jump at typical rotation speeds (mostly rational fractions of the rotation speed). The nonlinear behavior of the rigid rotor supported on foil bearings is also emphasized by varying the added unbalance: with increasing unbalance the vibration spectrum becomes gradually more diverse as new subsynchronous vibrations appear. The experimental results are compared with very simplified theoretical predictions based on the assumption that the air film in the two bearings is infinitely stiff compared to the foil structure. The latter is characterized by a cubic stiffness and a structural damping coefficient. The comparisons show only a rough qualitative agreement.
Adaptation of Energy Dissipation in a Mechanical Metastable Module Excited Near Resonance
Authors: Kidambi N. , Harne R. L. , Wang K. W.
Published: August 2015

Recent studies have demonstrated that the energetic vibrations of strategically designed negative stiffness inclusions may lead to large and adaptable damping in structural/material systems. Many researchers examine these features using models of bistable elements. From the viewpoint of system integration, bistable, negative stiffness elements often interface with positive stiffness elastic members. Under such conditions, the structural/material system may exhibit coexisting metastable states. In other words, the macroscopic displacement/strain remains fixed while the reaction force may vary due to internal change, similar to a phase transition. This coexistence of metastable states is not manifested in an individual (stand-alone) bistable element. Although the static and low frequency linear dynamics of structural/material systems possessing coexisting metastable states have been explored, much remains to be understood regarding the dynamics and energy dissipation characteristics of such systems when excited near resonance, where nonlinear dynamics are more easily activated and damping design is of greater importance. Thus, to effectively elucidate the enhanced versatility of damping properties afforded by exploiting negative stiffness inclusions in structural/material systems, this research investigates a mechanical module which leverages a coexistence of metastable states: an archetypal building block for system assembly. The studies employ analytical, numerical, and experimental findings to probe how near-resonant excitation can trigger multiple dynamic states, each resulting in distinct energy dissipation features. It is shown that, for lightly damped metastable mechanical modules, the effective energy dissipation may be varied across orders of magnitude via tailoring design and excitation parameters.
Elastic Anisotropy of Trabecular Bone in the Elderly Human Vertebra
Authors: Unnikrishnan Ginu U. , Gallagher John A. , Hussein Amira I. , Barest Glenn D. , Morgan Elise F.
Published: August 2015

Knowledge of the nature of the elastic symmetry of trabecular bone is fundamental to the study of bone adaptation and failure. Previous studies have classified human vertebral trabecular bone as orthotropic or transversely isotropic but have typically obtained samples from only selected regions of the centrum. In this study, the elastic symmetry of human vertebral trabecular bone was characterized using microfinite element (μFE) analyses performed on 1019 cubic regions of side length equal to 5 mm, obtained via thorough sampling of the centrums of 18 human L1 vertebrae (age = 81.17 ± 7.7 yr; eight males and ten females). An optimization procedure was used to find the closest orthotropic representation of the resulting stiffness tensor for each cube. The orthotropic elastic constants and orientation of the principal elastic axes were then recorded for each cube and were compared to the constants predicted from Cowin's fabric-based constitutive model (Cowin, 1985, “The Relationship Between the Elasticity Tensor and the Fabric Tensor,” Mech. Mater., 4(2), pp. 137–147.) and the orientation of the principal axes of the fabric tensor, respectively. Deviations from orthotropy were quantified by the “orthotropic error” (van Rietbergen et al., 1996, “Direct Mechanics Assessment of Elastic Symmetries and Properties of Trabecular Bone Architecture,” J. Biomech., 29(12), pp. 1653–1657), and deviations from transverse isotropy were determined by statistical comparison of the secondary and tertiary elastic moduli. The orthotropic error was greater than 50% for nearly half of the cubes, and the secondary and tertiary moduli differed from one another (p < 0.0001). Both the orthotropic error and the difference between secondary and tertiary moduli decreased with increasing bone volume fraction (BV/TV; p ≤ 0.007). Considering only the cubes with an orthotropic error less than 50%, only moderate correlations were observed between the fabric-based and the μFE-computed elastic moduli (R2 ≥ 0.337; p < 0.0001). These results indicate that when using a criterion of 5 mm for a representative volume element (RVE), transverse isotropy or orthotropy cannot be assumed for elderly human vertebral trabecular bone. Particularly at low values of BV/TV, this criterion does not ensure applicability of theories of continuous media. In light of the very sparse and inhomogeneous microstructure found in the specimens analyzed in this study, further work is needed to establish guidelines for selecting a RVE within the aged vertebral centrum.
Incorporating Density and Temperature in the Stretched Exponential Model for Predicting Stress Relaxation Behavior of Polymer Foams
Authors: Barua Bipul , Saha Mrinal C.
Published: August 2015

This paper discusses an approach to incorporate density and temperature terms in the well-known stretched exponential (SE) model for predicting the stress relaxation behavior of polymer foams. We have developed this approach for closed-cell polyurethane foams (PUFs) and verified using experimental data for accuracy. The SE model was first examined using short-term experimental data to predict long-term stress relaxation behavior of PU solid (PUS). The corresponding model parameters were then extracted for PUS and two PUFs with different densities (PU404 and PU415) at three different test temperatures. Finally, an expression was developed in conjunction with the modified Gibson–Ashby relationship and the Arrhenius equation and validated for other foam density (PU420) and test temperatures. The predictions were found to be reasonably good with more than 90% accuracy.
Experimental Assessment of High Damping Rubber Under Combined Compression and Shear
Authors: Quaglini Virginio , Dubini Paolo , Vazzana Giacomo
Published: August 2015

High damping rubber (HDR) is used in the manufacturing of elastomeric bearings for seismic isolation of building and structures. In practical situations, rubber bearings are subjected to a permanent vertical load which may change at the occurrence of the earthquake, and concurrent shear deformation, due to either service movements of the structure or earthquake-induced ground motion. The study presents an experimental procedure for the assessment of HDR specimens under combined compression and shear, reproducing the same typical load regimes which rubber isolators experience in service. Five commercial HDRs were tested according to the procedure. The results point to the importance of considering the influence of the compression stress for a correct understanding of the behavior of HDRs under cyclic shear.
Global Linear Instability of Flow Through a Converging–Diverging Channel
Authors: Jotkar Mamta R. , Swaminathan Gayathri , Sahu Kirti Chandra , Govindarajan Rama
Published: August 2015

The global linear stability, where we assume no homogeneity in either of the spatial directions, of a two-dimensional laminar base flow through a spatially periodic converging–diverging channel is studied at low Reynolds numbers. A large wall-waviness amplitude is used to achieve instability at critical Reynolds numbers below ten. This is in contrast to earlier studies, which were at lower wall-waviness amplitude and had critical Reynolds numbers an order of magnitude higher. Moreover, our leading mode is a symmetry-breaking standing mode, unlike the traveling modes which are standard at higher Reynolds numbers. Eigenvalues in the spectrum lie on distinct branches, showing varied structure spanning the geometry. Our global stability study suggests that such modes can be tailored to give enhanced mixing in microchannels at low Reynolds numbers.
Effect of Rub-Grooves on Leakage and Windage Heating in Straight-Through Labyrinth Seals
Authors: Charan Nayak Kali , Dutta Pradip
Published: August 2015

Prediction of leakage flow and windage heating for labyrinth seals with honeycomb lands is critical in understanding gas turbine engine system performance and predicting its component life. There are several labyrinth seal configurations in use in gas turbines, and for each configuration, there are many geometric factors that can impact a seal's leakage and windage characteristics. One of the factors which has not been thoroughly investigated in previously published work is the presence of rub-grooves in the honeycomb land and its impact on seal performance. This paper describes the development of a numerical methodology aimed at studying this effect. Specifically, a three-dimensional (3D) computational fluid dynamics (CFD) model is developed utilizing commercial finite volume-based software incorporating the renormalization group (RNG) k-ε turbulence model. Using this model, a broad parametric study is conducted by varying honeycomb cell size and radial clearance for a four-tooth straight-through labyrinth seal with and without rub-grooves. The results show good agreement with available experimental data. They further indicate that presence of rub-grooves increases seal leakage and decreases windage heating. The absolute levels depend on the clearance and honeycomb cell size.
Diesel Spray Rate-of-Momentum Measurement Uncertainties and Diagnostic Considerations
Authors: Knox Benjamin W. , Franze Michael J. , Genzale Caroline L.
Published: August 2015

Interpretation of combustion and emissions outcomes in diesel engines is often enhanced by accurate knowledge of the transient fuel delivery rate and flow characteristics of the injector nozzle. Important physical characteristics of these flows, including velocity profile and flow separation or cavitation effects, are difficult to measure directly, but can be characterized from a flow-averaged perspective through the measurement of nozzle flow coefficients, namely, the discharge, velocity, and area-contraction coefficients. Both the transient fuel mass flow rate and the flow-averaged nozzle coefficients can be found by measuring the mass and momentum flux of the fuel stream leaving the nozzle during injection through the application of an impingement technique, where fuel is sprayed onto the face of a transducer calibrated for force measurement in close proximity to the nozzle. While several published experiments have employed the spray impingement method to quantify rate of injection, the experimental setup and equipment selections vary widely and may contribute to disagreements in measured rate of injection. This paper identifies and provides estimates of measurement uncertainties that can arise when employing different experimental setups using the impingement method. It was observed that the impingement technique was sensitive to the design of the strike cap, specifically the contact area between the cap and transducer diaphragm, in addition to fuel temperature. Conversely, we observed that the impingement technique was relatively insensitive to angular and vertical misalignment, where the uncertainty can be estimated using control volume analysis. Transducer selection, specifically those with low acceleration sensitivity, high resonant frequency, and integrated electronics piezoelectric circuitry, substantially reduces the noise in the measurement.
Comparison of the Load-Carrying Performance of Mechanical Gas Seals Textured With Microgrooves and Microdimples
Authors: Shi Liping , Wang Xiuying , Su Xiao , Huang Wei , Wang Xiaolei
Published: August 2015

The effects of microgrooves and microdimples on the load-carrying performance of mechanical gas seals are compared in this study. Numerical model based on the Reynolds equation for compressible Newtonian fluid is utilized to investigate the load-carrying performance including the hydrodynamic pressure, the load-carrying force, and gas film stiffness of the gas seals. The results indicate that both microgrooves and microdimples can improve the load-carrying performance of mechanical gas seals, particularly under a small clearance condition. Furthermore, different texture patterns achieve optimal load-carrying performance at different area density, seal clearance, and depth: microgrooves with a low area density can obtain higher load-carrying force and gas film stiffness than the dimple patterns, but with high area density, elliptical dimples yield better load-carrying performance than the groove patterns.
Effect of Ingress on Turbine Disks
Authors: Cho GeonHwan , Sangan Carl M. , Michael Owen J. , Lock Gary D.
Published: August 2015

The ingress of hot gas through the rim seal of a gas turbine depends on the pressure difference between the mainstream flow in the turbine annulus and that in the wheel-space radially inward of the seal. This paper describes experimental measurements which quantify the effect of ingress on both the stator and rotor disks in a wheel-space pressurized by sealing flow. Infrared (IR) sensors were developed and calibrated to accurately measure the temperature history of the rotating disk surface during a transient experiment, leading to an adiabatic effectiveness. The performance of four generic (though engine-representative) single- and double-clearance seals was assessed in terms of the variation of adiabatic effectiveness with sealing flow rate. The measurements identify a so-called thermal buffering effect, where the boundary layer on the rotor protects the disk from the effects of ingress. It was shown that the effectiveness on the rotor was significantly higher than the equivalent stator effectiveness for all rim seals tested. Although the ingress through the rim seal is a consequence of an unsteady, three-dimensional flow field, and the cause–effect relationship between pressure and the sealing effectiveness is complex, the time-averaged experimental data are shown to be successfully predicted by relatively simple semi-empirical models, which are described in a separate paper. Of particular interest to the designer, significant ingress can enter the wheel-space before its effect is sensed by the rotor.
Effects of Grease Characteristics on Sound and Vibration of a Linear-Guideway Type Recirculating Ball Bearing
Authors: Ohta Hiroyuki , Tsuruoka Tatsuya , Fujinami Yukitoshi , Kato Soichiro
Published: August 2015

This paper deals with the effects of grease characteristics on sound and vibration of a linear-guideway type ball bearing. First, sound, vibration, and temperature of a linear-guideway type ball bearing were measured by changing 16 types of greases. Next, in order to explain the effects of grease characteristics (absolute viscosity η0 of the base oil in the grease at atmospheric pressure, pressure–viscosity coefficient ξ of the base oil, and penetration P of grease) and linear velocity V on the sound pressure p and vibratory acceleration a of the linear bearing, dimensional analyses were carried out. The dimensional analyses derived dimensionless products Pp/(η0V) and η0ξV/P for the sound, and dimensionless products Pa/V2 and η0ξV/P for the vibration. The plot of the measured data using dimensionless products showed that both sound pressure p and vibratory acceleration a (under a certain linear velocity) decreased as the absolute viscosity η0 of the base oil in the grease at atmospheric pressure or the pressure–viscosity coefficient ξ increased. Whereas the sound pressure p decreased as the penetration P decreased, the vibratory acceleration a decreased as P increased.
On the Equivalence of Acoustic Impedance and Squeeze Film Impedance in Micromechanical Resonators
Authors: Kaur Malhi Charanjeet , Pratap Rudra
Published: August 2015

In this work, we address the issue of modeling squeeze film damping in nontrivial geometries that are not amenable to analytical solutions. The design and analysis of microelectromechanical systems (MEMS) resonators, especially those that use platelike two-dimensional structures, require structural dynamic response over the entire range of frequencies of interest. This response calculation typically involves the analysis of squeeze film effects and acoustic radiation losses. The acoustic analysis of vibrating plates is a very well understood problem that is routinely carried out using the equivalent electrical circuits that employ lumped parameters (LP) for acoustic impedance. Here, we present a method to use the same circuit with the same elements to account for the squeeze film effects as well by establishing an equivalence between the parameters of the two domains through a rescaled equivalent relationship between the acoustic impedance and the squeeze film impedance. Our analysis is based on a simple observation that the squeeze film impedance rescaled by a factor of jω, where ω is the frequency of oscillation, qualitatively mimics the acoustic impedance over a large frequency range. We present a method to curvefit the numerically simulated stiffness and damping coefficients which are obtained using finite element analysis (FEA) analysis. A significant advantage of the proposed method is that it is applicable to any trivial/nontrivial geometry. It requires very limited finite element method (FEM) runs within the frequency range of interest, hence reducing the computational cost, yet modeling the behavior in the entire range accurately. We demonstrate the method using one trivial and one nontrivial geometry.
Gas Pipeline Failure Caused by In-Service Welding
Authors: Farzadi A.
Published: August 2015

In the research presented in this paper, a failure analysis had been carried out to identify causes of an incident, which had taken place after an operation to repair a leak in an interstate natural gas pipeline. In this operation, a partial encirclement reinforcement (patch) was welded to the carrier pipe according to an available hot taping procedure, while gas was flowing in the pipeline. The failure analysis commenced with preliminary steps of information gathering of background data regarding the repair operation and then several samples were extracted for macroscopic and microscopic metallurgical examinations. In addition to fractographic analyses of fracture surfaces, pipe material was examined because the pipeline had been in service for prolonged period and there was not any official material information available. The analyses disclose that hydrogen-assisted cracking, wrong design of branch connection, paint coating, and pipeline operating conditions were major factors contributing to the failure. The work undertaken also included development and recommendation of a repair procedure to avoid similar failures in the future.
Uncertainty Quantification Using Streamline Based Inversion and Distance Based Clustering
Authors: Park Jihoon , Jin Jeongwoo , Choe Jonggeun
Published: August 2015

For decision making, it is crucial to have proper reservoir characterization and uncertainty assessment of reservoir performances. Since initial models constructed with limited data have high uncertainty, it is essential to integrate both static and dynamic data for reliable future predictions. Uncertainty quantification is computationally demanding because it requires a lot of iterative forward simulations and optimizations in a single history matching, and multiple realizations of reservoir models should be computed. In this paper, a methodology is proposed to rapidly quantify uncertainties by combining streamline-based inversion and distance-based clustering. A distance between each reservoir model is defined as the norm of differences of generalized travel time (GTT) vectors. Then, reservoir models are grouped according to the distances and representative models are selected from each group. Inversions are performed on the representative models instead of using all models. We use generalized travel time inversion (GTTI) for the integration of dynamic data to overcome high nonlinearity and take advantage of computational efficiency. It is verified that the proposed method gathers models with both similar dynamic responses and permeability distribution. It also assesses the uncertainty of reservoir performances reliably, while reducing the amount of calculations significantly by using the representative models.
Linear cochlear mechanics
Authors: Zweig George
Published: August 2015

An active, three-dimensional, short-wavelength model of cochlear mechanics is derived from an older, one-dimensional, long-wavelength model containing time-delay forces. Remarkably, the long-wavelength model with nonlocal temporal interactions behaves like a short-wavelength model with instantaneous interactions. The cochlear oscillators are driven both by the pressure and its time derivative, the latter presumably a proxy for forces contributed by outer hair cells. The admittance in the short-wavelength region is used to find an integral representation of the transfer function valid for all wavelengths. There are only two free parameters: the pole position in the complex frequency plane of the admittance, and the slope of the transfer-function phase at low frequencies. The new model predicts a dip in amplitude and a corresponding rapid drop in phase, past the peak of the traveling wave. Linear models may be compared by their wavelengths, and if they have the same dimension, by the singularity structure of their admittances.
A phase space approach to wave propagation with dispersion
Authors: Ben-Benjamin Jonathan S. , Cohen Leon , Loughlin Patrick J.
Published: August 2015

A phase space approximation method for linear dispersive wave propagation with arbitrary initial conditions is developed. The results expand on a previous approximation in terms of the Wigner distribution of a single mode. In contrast to this previously considered single-mode case, the approximation presented here is for the full wave and is obtained by a different approach. This solution requires one to obtain (i) the initial modal functions from the given initial wave, and (ii) the initial cross-Wigner distribution between different modal functions. The full wave is the sum of modal functions. The approximation is obtained for general linear wave equations by transforming the equations to phase space, and then solving in the new domain. It is shown that each modal function of the wave satisfies a Schrödinger-type equation where the equivalent “Hamiltonian” operator is the dispersion relation corresponding to the mode and where the wavenumber is replaced by the wavenumber operator. Application to the beam equation is considered to illustrate the approach.
Republished: Accuracy in interpreting the paediatric ECG: a UK-wide study and the need for improvement
Authors: Jheeta Jatinder S , Narayan Omendra , Krasemann Thomas
Published: August 2015

Background

Paediatric ECG interpretation is significant for informed treatment of several conditions. Formal training in paediatric ECG is rarely undertaken.

Methods

A prospective survey based study module of UK-wide paediatricians registered with the UK Royal College of Paediatricians and Child Health (RCPCH) was conducted. 10 common clinical conditions seen in paediatrics for which there are recognisable ECGs had to be interpreted. After provision of an educational page, 10 further ECGs were presented.

Findings

8450 RCPCH members were emailed a link to the online survey–study module, of whom 764 participated. Of these, 493 interpreted the first 10 ECGs, and 385 interpreted both sets of ECGs. The accuracy for the first ECGs was 61.5% (63.5% for those who participated in the whole survey), and after use of the educational page increased to 73.3%. This was independent from previous ECG training.

Conclusions

The use of an easily accessible online educational page improved the accuracy of paediatric ECG interpretation significantly. Internet based education can improve the accuracy of paediatric ECG interpretation and should be developed further.
17β-Estradiol induces odontoblastic differentiation via activation of the c-Src/MAPK pathway in human dental pulp cells
Authors: Woo Su Mi , Seong Kyung Joo , Oh Sang Jin , Park Hong Ju , Kim Sun Hun , Kim Won Jae , Jung Ji Yeon
Published: August 2015

The present study is aimed at investigating the effects of the exogenous estrogen 17β-estradiol (E2) on odontoblastic differentiation in human dental pulp cells (HDPCs) immotalized with hTERT gene and their molecular mechanism. Proliferation was detected by BrdU assay, and odontoblast differentiation induction was evaluated by the expression of dentin sialophosphoprotein (DSPP), dentin sialoprotein (DSP) and dentin matrix protein1 (DMP1), and alkaline phosphatase (ALP) activity and mineralization. Estrogen receptor-α (ER-α), c-Src, and mitogen-activated protein kinases (MAPKs) were examined and their inhibitors were used to determine the roles on odontogenic induction. E2 significantly promoted the HDPC proliferation, which was mediated by extracellular signal-related kinase 1/2. E2 upregulated DSPP, DSP, and DMP1 as the odontogenic differentiation markers and enhanced ALP activity and mineralization. E2 increased phosphorylation of ER-α and fulvestrant, an ER downregulator, significantly downregulated DSPP, DMP1, and DSP induced by E2. Moreover, E2 treatment activated c-Src and MAPKs upon odontogenic induction, whereas chemical inhibition of c-Src and MAPKs decreased expression of DSPP, DMP1, and DSP and mineralization augmented by E2. Moreover, fulvestrant reduced E2-induced phosphorylation of c-Src and MAPK and inhibition of c-Src by PP2 attenuated activation of MAPKs during E2-induced odontoblastic differentiation. Taken together, these results indicated that E2 stimulates odontoblastic differentiation of HDPCs via coordinated regulation of ER-α, c-Src, and MAPK signaling pathways, which may play a key role in the regeneration of dentin.
Experimental and numerical study on determination of indirect (splitting) tensile strength of rocks under various load apparatus
Authors: Komurlu Eren , Kesimal Ayhan , Demir Serhat
Published: August 2015

The indirect tensile strengths (ITSs) of more than 200 disc specimens for 19 different rock and rock-like materials were determined by considering the concept of fracture toughness under different loading conditions. Steel loading arcs with various contact angles and flat platens were used in experiments to investigate whether they can be used as alternatives for the standard Brazilian jaw. Many of the disc specimens tested under the standard jaw did not fail with ideal tensile cracking at the centre, whereas simple splitting cracks were obtained along the vertical diameter of most of the discs tested under the flat platens. However, flat platens caused cracks to initiate in the compressive zone just under the loading points. This is an important outcome for criticizing the validity of the test because tensile failure is expected to occur along the vertical diameter of the disc. Friction conditions between the disc and jaw have important roles in the failing load. Moreover, fracture toughness is an additional parameter for investigating the ITSs of rock materials. According to the experimental results, fracture toughness values were found to increase with an increase in contact angle. In addition to the experimental study, finite element analyses were performed on several types of rock discs under various loading conditions. As a result, a comparison between all loading conditions was made to determine the best ITSs of the rocks. Both experimental and numerical analyses concluded that deciding the best loading type depends on the rock type. Therefore, the standard jaw is not recommended to use for determination of the ITS values of all rock types.
Accelerated rare event sampling
Authors: Yevick David
Published: August 2015

A sampling procedure for the transition matrix Monte Carlo method is introduced that generates the density of states function over a wide parameter range with minimal coding effort.
R-modes in neutron stars: Theory and observations
Authors: Haskell B.
Published: August 2015

In this paper, I will review the theory behind the gravitational wave (GW) driven r-mode instability in rapidly rotating neutron stars (NSs) and discuss which constraints can be derived from observations of spins and temperatures in low mass X-ray binaries (LMXBs). I will discuss how a standard, 'minimal' NS model is not consistent with the data, and discuss some of the additional physical mechanisms that could reconcile theory with observations. In particular, I will focus on additional forms of damping due to exotic cores and on strong mutual friction due to superfluid vortices cutting through superconducting flux tubes, and examine the repercussions these effects could have on the saturation amplitude of the mode. Finally I will also discuss the possibility that oscillations due to r-modes may have been recently observed in the X-ray light curves of two LMXBs.
On the number of representations of integers by sums of mixed numbers
Authors: Xia Ernest X. W. , Ma Y. H. , Tian L. X.
Published: August 2015

In this paper, several explicit formulas for the number of representations of a positive integer by sums of mixed numbers are determined by employing theta function identities and the [Formula: see text]-parametrization of theta functions due to Alaca, Alaca and Williams. It is interesting that the formulas proved in this paper are linear combinations of [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text].
Magnetostrictive gradient in Tb0.27Dy0.73Fe1.95 induced by high magnetic field gradient applied during solidification
Authors: Gao Pengfei , Liu Tie , Dong Meng , Yuan Yi , Wang Kai , Wang Qiang
Published: August 2015

We investigated how high magnetic field gradients affected the magnetostrictive performance of Tb[Formula: see text]Dy[Formula: see text]Fe[Formula: see text] during solidification. At high applied magnetic field gradients, the magnetostriction exhibited a gradient distribution throughout the alloy. Increasing the magnetic field gradient also increased the magnetostriction gradient. We attributed the graded magnetostrictive performance to the gradient distribution of (Tb, Dy)Fe2 phase in the alloy and its orientation.
3D Artifacts Similarity Based on the Concurrent Evaluation of Heterogeneous Properties
Authors: Biasotti Silvia , Cerri Andrea , Falcidieno Bianca , Spagnuolo Michela
Published: August 2015

Archaeological artifacts are often classified in homogeneous groups, according to either intangible properties (e.g., origin, use, age) or physical features (e.g., color, material, geometric shape, size, style). In particular, a single property is usually not enough to characterize artifacts’ peculiar traits, as most of the objects are affected by degradation or only partially preserved. In this article, we propose a shape analysis and comparison pipeline specifically targeted to the similarity assessment of real-world 3D artifacts. The proposed methodology is able to concurrently evaluate heterogeneous properties, such as geometric (e.g., curvature, size, roundness, or mass distribution) and photometric (e.g., texture, color distribution, or reflectance) aspects. The geometric description is based on a statistical technique to select properties that are mutually independent; the photometric information is handled according to a topological perspective and complemented by the analysis of color distribution. The outcome is a mixed description of each 3D artifact, which is used to derive a similarity measure between objects. The potential of our approach is high because any property representable as real- or vector- valued functions can be easily added in our framework. Experimental results carried on an existing collection of textured triangle meshes are exhibited to show the potentiality of the method in retrieval and classification tasks.
Behavioral Subtyping, Specification Inheritance, and Modular Reasoning
Authors: Leavens Gary T. , Naumann David A.
Published: August 2015

Verification of a dynamically dispatched method call,
E
.
m
(), seems to depend on
E
’s dynamic type. To avoid case analysis and allow incremental development, object-oriented program verification uses supertype abstraction. In other words, one reasons about
E
.
m
() using
m
’s specification for
E
’s static type. Supertype abstraction is valid when each subtype in the program is a behavioral subtype. This article semantically formalizes supertype abstraction and behavioral subtyping for a Java-like sequential language with mutation and proves that behavioral subtyping is both necessary and sufficient for the validity of supertype abstraction. Specification inheritance, as in JML, is also formalized and proved to entail behavioral subtyping.
DL-Lite Ontology Revision Based on An Alternative Semantic Characterization
Authors: Wang Zhe , Wang Kewen , Topor Rodney
Published: August 2015

Ontology engineering and maintenance require (semi-)automated ontology change operations. Intensive research has been conducted on TBox and ABox changes in description logics (DLs), and various change operators have been proposed in the literature. Existing operators largely fall into two categories: syntax-based and model-based. While each approach has its advantages and disadvantages, an important topic that has rarely been explored is how to achieve a balance between syntax-based and model-based approaches. Also, most existing operators are specially designed for either TBox change
or
ABox change, and cannot handle the general ontology revision task—given a DL knowledge base (KB, a pair consisting of a TBox and an ABox), how to revise it by a set of TBox and ABox axioms (
i.e.
, a new DL KB). In this article, we introduce an alternative structure for DL-Lite, called a featured interpretation, and show that featured models provide a finite and tight characterization to the classical semantics of DL-Lite. A key issue for defining a change operator is the so-called expressibility, that is, whether a set of models (or featured models here) is axiomatizable in DLs. It is indeed much easier to obtain expressibility results for featured models than for classical DL models. As a result, the new semantics determined by featured models provides a method for defining and studying various changes of DL-Lite KBs that involve both TBoxes and ABoxes. To demonstrate the usefulness of the new semantic characterization in ontology change, we define two revision operators for DL-Lite KBs using featured models and study their properties. In particular, we show that our two operators both satisfy AGM postulates. We show that the complexity of our revisions is Π

P

2
-complete, that is, on the same level as major revision operators in propositional logic, which further justifies the feasibility of our revision approach for DL-Lite. Also, we develop algorithms for these DL-Lite revisions.
The BigDAWG Polystore System
Authors: Duggan Jennie , Elmore Aaron J. , Stonebraker Michael , Balazinska Magda , Howe Bill , Kepner Jeremy , Madden Sam , Maier David , Mattson Tim , Zdonik Stan
Published: August 2015

This paper presents a new view of federated databases to address the growing need for managing information that spans multiple data models. This trend is fueled by the proliferation of storage engines and query languages based on the observation that 'no one size fits all'. To address this shift, we propose a polystore architecture; it is designed to unify querying over multiple data models. We consider the challenges and opportunities associated with polystores. Open questions in this space revolve around query optimization and the assignment of objects to storage engines. We introduce our approach to these topics and discuss our prototype in the context of the Intel Science and Technology Center for Big Data
In-memory Databases
Authors: Tan Kian-Lee , Cai Qingchao , Ooi Beng Chin , Wong Weng-Fai , Yao Chang , Zhang Hao
Published: August 2015

The increase in the capacity of main memory coupled with the decrease in cost has fueled research in and development of in-memory databases. In recent years, the emergence of new hardware has further given rise to new challenges which have attracted a lot of attention from the research community. In particular, it is widely accepted that hardware solutions can provide promising alternatives for realizing the full potential of in-memory systems. Here, we argue that naive adoption of hardware solutions does not guarantee superior performance over software solutions, and identify problems in such hardware solutions that limit their performance. We also highlight the primary challenges faced by in-memory databases, and summarize their potential solutions, from both software and hardware perspectives
Forgetful Digital Memory
Authors: Niederee Claudia , Kanhabua Nattiya , Gallo Francesco , Logie Robert H.
Published: August 2015

With the growing volumes of and reliance on digital content, there is a clear need for better information managementapproaches that keep relevant information accessible and usable in long-term encapsulated together with the evolving context information that is needed for its interpretation. Inspired by the role of forgetting in the human brain, in this paper, we envision a concept of managed forgetting for systematically dealing with information that progressively ceases in importance and also with redundant information - leading to a form of Forgetful Digital Memory. Managed forgetting is meant to complement rather than copy human remembering and forgetting. It can be regarded as functions of attention and significance dynamics relying on multi-faceted information assessment. Its goal is to introduce an alternative to the dominating 'keep-it-all' strategy for digital content, which ensures that the important content is kept safe, useful, and understandable over time
Data Series Management
Authors: Palpanas Themis
Published: August 2015

Massive data series collections are becoming a reality for virtually every scientific and social domain, and have to be processed and analyzed, in order to extract useful knowledge. Current data series management solutions are ad hoc, requiring huge investments in time and effort, and duplication of effort across different teams. Systems like relational databases, Column Stores, and Array Databases are not a suitable solution either, since none of these systems offers native support for data series. Our vision is to design and develop a generalpurpose Data Series Management System, able to copewith big data series, that is, very large and fast-changing collections of data series, which can be heterogeneous (i.e., originate from disparate domains and thus exhibit very different characteristics), and which can have uncertainty in their values (e.g., due to inherent errors in the measurements). Just like databases abstracted the relational data management problem and offered a black box solution that is now omnipresent, the proposed system will allow analysts that are not experts in data series management, as well as common users, to tap in the goldmine of the massive and ever-growing data series collections they (already) have
An ISO-based software process ontology pattern language and its application for harmonizing standards
Authors: Ruy Fabiano B. , Falbo Ricardo A. , Barcellos Monalessa P. , Guizzardi Giancarlo , Quirino Glaice K. S.
Published: August 2015

Many efforts have been made for modeling and standardizing software processes. ISO/IEC JTC1/SC7, the ISO sub-committee responsible for software and systems engineering, is one of the most important groups devoted to this task. However, standards developed by this committee are frequently inconsistent and even contradictory. This led to the need for an ISO Study Group to investigate the creation of an ontological infrastructure to establish a common conceptualization for underpinning all SC7 standards. This ISO initiative is a work in progress, which has focused on the software process domain and, in particular, considering the ISO/IEC 24744 standard. In this paper, we advocate in favor of using an Ontology Pattern Language (OPL) as the main component of this ontological infrastructure. We present ISP-OPL (ISO-based Software Process OPL), an OPL that can be applied as a basis for harmonizing software process-related ISO standards, favoring reuse when building aligned specific software process ontologies for Software Engineering sub-domains. In order to evaluate its applicability, we conducted an experiment involving seven domain ontologies, developed using ISP-OPL.
Towards persuasive social recommendation
Authors: Palanca Javier , Heras Stella , Jorge Javier , Julian Vicente
Published: August 2015

The exponential growth of social networks makes fingerprint let by users on the Internet a great source of information, with data about their preferences, needs, goals, profile and social environment. These data are distributed across different sources of information (social networks, blogs, databases, etc.) that may contain inconsistencies and their accuracy is uncertain. Paradoxically, this unprecedented availability of heterogeneous data has meant that users have more information available than they actually are able to process and understand to extract useful knowledge from it. Therefore, new tools that help users in their decision-making processes within the network (e.g. which friends to contact with or which products to consume) are needed. In this paper, we show how we have used a graph-based model to extract and model data and transform it in valuable knowledge to develop a persuasive social recommendation system.
Data-parallel structural optimisation in agent-based models
Authors: Husselmann Alwyn V.
Published: August 2015

Agent-based models offer valuable simulations of various phenomena found in disciplines such as ecology [1], microbiology [2] and social science [3]. Even the spatial distribution of crime can be simulated [4] using this method. Representing discrete entities in a system as autonomous, interactive and situated in some manner, gives rise to the notion of "bottom-up" modelling, as opposed to "top-down" approaches commonly done using partial differential equations [5]. While not considered a replacement for these, agent-based modelling (ABM) is another potent computational science tool.