bluuebunny/crossref_metadata_2025 huggingface dataset:
Study and Verification of Continuous Adjoint System for Aerodynamic Optimization in Turbomachinery Cascades
Authors: Zhang Pengfei , Li Haitao , Feng Zhenping
Published: November 2013

This paper is a further study of the authors’ previous work on the continuous adjoint method based on the variation in grid node coordinates and Jacobi Matrices of the flow fluxes. This method simplifies the derivation and expression of the adjoint system, and reduces the computation cost. In this paper, the differences between the presented and the traditional methods are analyzed in details by comparing the derivation processes and the adjoint systems. In order to demonstrate the reliability and accuracy of the adjoint system deduced by the authors, the presented method is applied to different optimal problems, which include two inverse designs and two shape optimizations in both 2D and 3D cascades. The inverse designs are implemented by giving the isentropic Mach number distributions along the blade wall for 2D inviscid flow and 3D laminar flow. The shape optimizations are implemented with the objective function of the entropy generation in flow passage for 2D and 3D laminar flows. In the 3D optimal case, this method is validated by supersonic turbine design case with and without mass flow rate constraint. The numerical results testify the accuracy of this adjoint method, which includes only the boundary integrals, and furthermore, the universality and portability of this adjoint system for inverse designs and shape optimizations are demonstrated.
Study of Shock/Blade Tip Leakage Vortex/Boundary Layer Interaction in a Transonic Rotor With IDDES Method
Authors: Shi Ke , Fu Song
Published: November 2013

In the present study, Improved Delayed Detached Eddy Simulation (IDDES) based on k-ω-SST turbulence model is applied to study the unsteady phenomenon in a transonic compressor rotor. Particular emphasis is on the understanding of the complex underlying mechanisms for the flow unsteadiness caused by the interaction of passage shock, blade tip leakage vortex (BTLV) and the blade boundary layer. The sources of the significant unsteadiness of the flow are shown. At the lower span height, where the BTLV is far away, the shock wave ahead of the blade leading edge impinges on the suction surface boundary layer of the adjacent blade, causing the shock wave/boundary layer interaction (SWBLI). Boundary layer thickness grows, while flow separates after the interaction. Predicted by IDDES calculation, this shock-induced separation exists as a separation bubble. The flow reattaches very soon after separation. At the near tip region, the shock wave surface deforms due to the strong interaction between the shock and the BTLV. Oscillation of the shock wave surface near the vortex core infers an unsteady contend between the shock and the vortex. Iso-surfaces of the Q parameter are applied to identify the vortex and its structure. Normally, the vortex breakdown in the rotor passage will lead to stall. However, in the present transonic case, the vortex breakdown was observed even at the near peak efficiency point. While the mass flow rate decreases, the shock waves formed ahead of the rotor blade leading edge were pushed upstream, causing earlier casing wall boundary layer separation. Upstream moving behavior of the shock is considered a new stall process.
Use of POD Method to Elucidate the Physics of Unsteady Micro-Pulsed-Jet Flow for Boundary Layer Flow Separation Control
Authors: Zhu Jianfeng , Huang Guoping , Fu Xin , Fu Yong , Yu Haibin
Published: November 2013

This paper presents a micro pulsed aspirated jet concept to suppress the flow separation in compressors. According to this concept, a kind of pulsed jet and an imitating cascade channel has been established; the characteristic frequency of separation vortex is about 266Hz. The experimental and numerical investigation about the unsteady frequency has been finished, and when the frequency of pulsed jet is close to the characteristic frequency of separation vortex, the control effects are more obvious. Based on the numerical results, the proper orthogonal decomposition (POD) method is introduced to analyze the unsteady control mechanism, and the spatial and temporal structure of unsteady flow field can be decoupled by POD method. The POD analysis results show that the main effect of unsteady pulsed jet is reallocating the energy of each mode, and selectively strengthening or weakening certain modes; the effect of steady jet is overall reducing the energy of high order modes. Based on the reasonable control parameters of pulsed jet, the energy in higher modes will be transferred to the average flow mode, and the translation of modal energy is coming from the reconstructing of spatial flow structures and the ordering of modal evolution characteristic. Finally, the validation of experimental investigation has been finished; and the credibility of the analysis is also enhanced.
Direct Numerical Simulations of Laminar Separation Bubbles on a Curved Plate: Part 1 — Simulation Setup and Uncontrolled Flow
Authors: Balzer Wolfgang , Fasel Hermann F.
Published: November 2013

The aerodynamic performance of lifting surfaces operating at low Reynolds number conditions is impaired by laminar separation. For a modern low-pressure turbine (LPT) stage, in particular when designed for high blade loadings, laminar separation at cruise conditions can result in significant performance degradation. Understanding of the physical mechanisms and hydrodynamic instabilities that are associated with laminar separation and the formation of laminar separation bubbles (LSBs) is key for the design and development of effective and efficient active flow control (AFC) devices. For the present work, laminar separation (part I) and its control (part II) were investigated numerically by employing highly-resolved, high-order accurate direct numerical simulations (DNS).
Uncertainties of an Automated Optical 3D Geometry Measurement, Modeling, and Analysis Process for Mistuned IBR Reverse Engineering
Authors: Kaszynski Alexander , Beck Joseph A. , Brown Jeffrey M.
Published: November 2013

An automated reverse engineering process is developed that uses a structured light optical measurement system to collect dense point cloud geometry representations. The modeling process is automated through integration of software for point cloud processing, reverse engineering, solid model creation, grid generation, and structural solution. Process uncertainties are quantified on a calibration block and demonstrated on an academic transonic integrally bladed rotor. These uncertainties are propagated through physics-based models to assess impacts on predicted modal and mistuned forced response. Process details are discussed and recommendations made on reducing uncertainty. Reverse engineered parts averaged a deviation of 0.0002 in. (5 μm) which did not significantly impact low and mid-range frequency responses. High frequency modes were found to be sensitive to these uncertainties demonstrating the need for future refinement of reverse engineering processes.
Improvement of a Theoretical Analysis Method for Tesla Turbines
Authors: Deng Qinghua , Qi Wenjiao , Feng Zhenping
Published: November 2013

A Tesla turbine makes use of a fluid’s viscous force to cause rotation of a set of closed spaced disks. In this paper, the theoretical analysis method proposed by Carey et al in 2010 was improved, and the design method has taken the pressure drop occurring in the rotor into consideration in order to approach its physics condition of flow. The sensitivity of the design parameters on the isentropic efficiency of Tesla turbines was investigated, and the results indicate that rotor tip Mach number is the most sensitive factor, followed in turn by the pressure ratio across the turbine, the specific heat ratio, the non-dimensional rotor radius ratio, the dimensionless inlet tangential velocity difference, and the modified Reynolds number. A typical Tesla turbine was designed and its flow characteristics were numerically simulated by 3-dimensional viscous governing equations. The results of numerical simulations show that the isentropic efficiency increases with the rotational speed and increasing turbine pressure ratio and as the nozzle number drops. The output power goes up with the rotational speed and increasing nozzle number, but decreases with increasing pressure ratio across the turbine. The highest isentropic efficiency 0.436 of the Tesla turbine supply with 2 nozzles is obtained with the pressure ratio 0.8 and the rotational speed 24,658r/min. Combining the influence of nozzle number on isentropic efficiency and output power, a Tesla turbine with two or four nozzles is suggested. Generally the results of numerical calculations show that they are in reasonably agreement with the results of design method, and are also consistent with the results of sensitivity analysis.
Numerical Investigation of the Unsteady Flow Inside a Centrifugal Compressor Stage With Pipe Diffuser
Authors: Grates Daniel R. , Jeschke Peter , Niehuis Reinhard
Published: November 2013

The subject of this paper is the investigation of unsteady flow inside a transonic centrifugal compressor stage with pipe-diffuser by utilizing unsteady 3D Navier-Stokes simulations (unsteady 3D URANS). The CFD results obtained are compared with detailed experimental data gathered using various steady and unsteady measurement techniques. The basic phenomena and mechanisms of the complex and highly unsteady flow inside the compressor with pipe-diffuser are presented and analyzed in detail.
Switching Action in Rotor-AMB Systems for Smooth Vibration Control
Authors: Wang Muhao , Sahinkaya M. Necip , Keogh Patrick S.
Published: November 2013

Rotating machines may, for reasons of gyroscopic coupling and aerodynamic influences, exhibit speed dependent characteristics. For systems that incorporate active magnetic bearings (AMBs) for rotor levitation, a range of control strategies are available for implementation to achieve desired closed loop dynamic characteristics. Over a large operating speed range, it may not be possible stabilize a rotor by using only one linear time-invariant (LTI) H∞ controller that has speed independent characteristics. This paper addresses that problem by introducing a switching controller system. The system contains a number of (LTI) H∞ controllers, designed to cover particular speed ranges, together with an external signal to drive the switching action. When speed dependent unbalance forcing acts, each of the controllers is able to attenuate vibration of the rotor over the specific speed ranges. The controller switching points are selected according to a metric that takes account of measured rotor lateral vibration. However, a sudden switching action may induce significant transient disturbance and give rise to rotor vibration overshoot, possibly to the extent of causing rotor-stator contact. To alleviate this problem, a ramp switching signal may be introduced such that two controllers may be switched smoothly over a given time period. Further smoothing modifications are possible to avoid ‘over-control’ and obtain a better transient performance. The unstable points of each H∞ controller are also discussed with respect to upper threshold speeds, above which controller switching is not allowable.
Experience With Gas Path Analysis for On-Wing Turbofan Condition Monitoring
Authors: Verbist Michel L. , Visser Wilfried P. J. , van Buijtenen Jos P.
Published: November 2013

Gas path analysis (GPA) is an effective method for determination of turbofan component condition from measured performance parameters. GPA is widely applied on engine test rig data to isolate components responsible for performance problems, thereby offering substantial cost saving potential. Additional benefits can be obtained from the application of GPA to on-wing engine data.

This paper describes the experience with model-based GPA on large volumes of on-wing measured performance data. Critical is the minimization of the GPA results uncertainty in order to maintain reliable diagnostics and condition monitoring information. This is especially challenging giving the variable in-flight operating conditions and limited on-wing sensor accuracy. The uncertainty effects can be mitigated by statistical analysis, and filtering and post-processing of the large datasets. By analyzing correlations between measured performance data trends and estimated component condition trends errors can be isolated from the GPA results. The various methods assessed are described and results are demonstrated in a number of case studies on a large turbofan engine fleet.
Unsteady Flow Modeling Using Transient Rotor–Stator Interface
Authors: Izmaylov Rudolf A. , Lopulalan Henry D. , Norimarna Gertruida S.
Published: November 2013

Based on experimental investigation of unsteady flow phenomena in centrifugal compressor, conducted in LPI (SPbSPU), including the measurements of high frequency pressure and hot-wire probes, numerical calculation was conducted with the aid of commercial ANSYS CFX12. The object was a model of industrial compressor, tested in full range of mass flows (from maximum to the onset of surge). Unsteady turbulent flows were calculated with URANS, turbulence model - SST-Menter. Region between the impeller and diffuser was calculated with Transient Method option. Time discretization Δ = 12 μsec. Sequential 20 revolutions of rotors were calculated, also LES model were used. Unsteady calculation results demonstrated reasonable agreement with experimental data both in meridional, and radial sections concerning the character of “jet – wakes” propagation, distribution of velocities in diffuser, and clearly showed three-dimensional flow conditions and reverse zones on the diffuser walls. “Frozen” velocity distributions during rotating stall demonstrated possibility of unsteady flow prediction with the aid of ANSYS CFX12. CFD results comparison with experimental data showed reasonable agreement for distributions of total pressures in diffuser, as well total and static characteristics of impeller and diffuser.
Application of Integral Geared Compressors in the Process Gas Industry
Authors: Srinivasan Anand , Impastato Chuck
Published: November 2013

The use of integral geared compressors (IGCs) is becoming increasingly popular in the process gas industry. IGCs offer certain unique advantages over inline type machines, making it ideally suited for real gas compression. Multiple rotor speeds can be effortlessly achieved by virtue of the gear ratios within each unit, thus resulting in an aerodynamically efficient design for the stages. The ability to cool the gas after every stage of compression using inter-coolers benefits the thermodynamic efficiencies. Multiple processes can be combined into one unit reducing overall costs and reduced real estate requirements. In this paper, the technical challenges associated with designing, building and testing these units have been presented. Case studies of applications of IGCs for real gas compression have also been presented.
Experimental Analysis of Flow Unbalance in Two Parallel Counter-Flow Recuperators
Authors: Martini Alessio , Traverso Alberto , Tucker David , VanOsdol John
Published: November 2013

The aim of this study was to provide a characterization of non-symmetrical operation in two counter-flow primary surface exhaust gas recuperators installed in parallel flow loops. The hybrid system emulator test rig and facility designed and operated by the Department of Energy, National Energy Technology Laboratory located at the West Virginia (USA) campus was used for the study. Various tests from the past years often resulted in non-symmetrical operation, indicated by significantly variant temperature measurements at the outlets of the recuperators.

Some specific tests have been carried out in order to identify the possible cause of this flow unbalance. The isolated effects of bleed air, cold air and hot air valve on the heat exchangers flow unbalance have been studied. Also, the impact of load bank changes on flow distribution has been considered in this study. Each test has been carried out in close loop fuel valve speed control. The influence of each independent variable in the study on parallel recuperator flow distribution has been quantitatively characterized using temperatures and a heat balance. Both the bleed and the cold air compressor bypass valves showed an appreciable impact on the heat exchangers flow unbalance, while hot air valve and load bank changes had minimal effect.
Design and Analysis of Wind Turbine Blades: Winglet, Tubercle, and Slotted
Authors: Gupta Alka , Alsultan Abdulrahman , Amano R. S. , Kumar Sourabh , Welsh Andrew D.
Published: November 2013

Energy is the heart of today’s civilization and the demand seems to be increasing with our growing population. Alternative energy solutions are the future of energy, whereas the fossil-based fuels are finite and deemed to become extinct. The design of the wind turbine blade is the main governing factor that affects power generation from the wind turbine. Different airfoils, angle of twist and blade dimensions are the parameters that control the efficiency of the wind turbine. This study is aimed at investigating the aerodynamic performance of the wind turbine blade. In the present paper, we discuss innovative blade designs using the NACA 4412 airfoil, comparing them with a straight swept blade. The wake region was measured in the lab with a straight blade. All the results with different designs of blades were compared for their performance. A complete three-dimensional computational analysis was carried out to compare the power generation in each case for different wind speeds. It was found from the numerical analysis that the slotted blade yielded the most power generation among the other blade designs.
The Application of the Norton-Bailey Law for Creep Prediction Through Power Law Regression
Authors: May D. L. , Gordon A. P. , Segletes D. S.
Published: November 2013

Accurate determination of constitutive modeling constants used in high value components, especially in electric power generation equipment, is vital for related design activities. Parts under creep are replaced after extensive deformation is reached, so models, such as the Norton-Bailey power law, support service life prediction and repair/replacement decisions. For high fidelity calculations, experimentally acquired creep data must be accurately regressed over a variety of temperature, stress, and time combinations. If these constants are not precise, then engineers could be potentially replacing components with lives that have been fractionally exhausted, or conversely, allowing components to operate that have already been exhausted. By manipulating the Norton-Bailey law and utilizing bivariate power-law statistical regression, a novel method is introduced to precisely calculate creep constants over a variety of sets of data. The limits of the approach are explored numerically and analytically.
Inverse Design of Turbine and Compressor Stages Using a Commercial CFD Program
Authors: Arbabi Araz , Ghaly Wahid
Published: November 2013

An aerodynamic inverse method that is developed for viscous flow over airfoils, is implemented into ANSYS-CFX as a User-Defined Function (UDF). The implementation is validated, it is then assessed in the redesign of a compressor and a turbine stage in two-dimensional visocus flow. In the inverse method, one of the design choices is to prescribe a target pressure distribution on the airfoil surfaces. The airfoil walls are assumed to be moving with a virtual velocity that would asymptotically drive the airfoil to the shape that would correspond to the specified target pressure distribution. This virtual velocity distribution is computed from the difference between the current and the target pressure distributions. The inverse design approach is fully consistent with the viscous flow assumption and is independent of the CFD approach taken. The Arbitrary Lagrangian-Eulerian formulation of the unsteady Reynolds-Averaged Navier Stokes equations is solved in a time accurate fashion with the airfoil motion being the source of unsteadiness. At each time step, the airfoil shape is modified and dynamic meshing is used to remesh the fluid flow domain. An axial compressor stage and turbine stage are redesigned using ANSYS-CFX running in inverse mode so as to demonstrate the ability of this approach to improve the aerodynamic performance of both compressor and turbine stages.
An Experimental and Theoretical Investigation of Wave Propagation in Teflon and Nylon Tubing With Methods to Prevent Aliasing in Pressure Scanners
Authors: Hurst Adam M. , VanDeWeert Joe
Published: November 2013

Accurate static and dynamic pressure measurements provide the feedback needed to advance gas turbine efficiency and reliability as well as improve aircraft design and flight control. During turbine testing and aircraft flight testing, flush mounting pressure transducers at the desired pressure measurement location is not always feasible and recess mounting with connective tubing is often used as an alternative. Resonances in the connective tubing can result in aliasing within pressure scanners even within a narrow bandwidth and especially when higher frequency content DC to ∼125Hz is desired. We present experimental results that investigate tube resonances and attenuation in 1.35mm inner diameter (ID) (used on 0.063in tubulations) and 2.69mm ID (used on 0.125in tubulations) Teflon and Nylon tubing at various lengths. We utilize a novel dynamic pressure generator, capable of creating large changes in air pressure (<1psi to 10psi, <6.8kPa to 68.9kPa), to determine the frequency response of such tubing from ∼1Hz to 2,800Hz. We further compare these experimental results to established analytical models for propagation of pressure disturbances in narrow tubes. While significant theoretical and experimental work relating to the frequency response of connective tubing or transmission lines has been published, there is limited literature presenting experimental frequency response data with air as the media in elastic tubing. In addition, little progress has been made in addressing the issue of tubing-related aliasing within pressure scanners, as the low sampling rate in scanners often makes post-processing antialiasing filters ineffective.

The experimental results and analytical models presented herein can be used as a guideline to prevent aliasing and signal distortion by guiding the proper design of pressure transmission systems, resulting in accurate static and dynamic pressure measurements with pressure scanners. The data presented here should serve as a reference to instrumentation engineers so that they can make higher frequency measurements (up to ∼125Hz, currently) and are able to quantify the expected pressure transmission line (tube) attenuation and know if aliasing will be a concern. This information will give engineers greater measurement capability when using pressure scanners to make static and dynamic pressure measurements.
The Philosopher’s Stone of Reprogramming
Authors: Schaefer Anne
Published: November 2013

A hierarchical transcriptional mechanism governs direct conversion of mouse embryonic fibroblasts to neurons.
Haemodialysis: hospital or home?
Authors: Power Albert , Ashby Damien
Published: November 2013

Healthcare costs associated with the provision of dialysis therapy are escalating globally as the number of patients developing end-stage renal disease increases. In this setting, there has been heightened interest in the application and potential benefit of home haemodialysis therapies compared with the conventional approach of thrice weekly, incentre treatments. Increasingly, national healthcare systems are financially incentivising the expansion of home haemodialysis programmes with observational studies demonstrating better patient survival, superior control of circulating volume and blood pressure, greater patient satisfaction and lower running costs compared with incentre dialysis. Nonetheless, increasing the prevalence of home haemodialysis is challenged by the technological complexity of conventional dialysis systems, the need for significant adaptations to the home as well as suboptimal clinician and patient education about the feasibility and availability of this modality. In addition, enthusiasm about frequent as well as nocturnal (extended-hours) haemodialysis has been tempered by results from the recent Frequent Haemodialysis Network randomised controlled trials comparing these schedules with a conventional incentre regime. An increasing emphasis on empowering patient choice and promoting self-management of chronic illness is a powerful driver for the expansion of home haemodialysis programmes in the UK and internationally.
Modeling flexural properties in white spruce (Picea glauca) and jack pine (Pinus banksiana) plantation trees
Authors: Vincent Manon , Duchesne Isabelle
Published: November 2013

Mixed models combining random coefficient effect and covariance patterns were used to investigate mechanical property variations in jack pine (Pinus banksiana Lamb.) and white spruce (Picea glauca (Moench) Voss) trees. Modulus of elasticity (MOE) and modulus of rupture (MOR) were measured by conducting three-point bending tests on small defect-free samples selected from different radial positions and at a height of 2.5 m above ground within the stems. The objective of the paper was to build statistical predictive models describing the radial variations in stems for wood mechanical properties using easily measurable explanatory variables that are typically available in the wood manufacturing industry: distance from pith, tree height and diameter, and spacing. The explanatory variables integrated into the models explained MOE adequately, whereas MOR appeared harder to predict with only these variables and at this resolution. For white spruce, the best mixed-effects models explained 80% and 61% of the variation in MOE and MOR, respectively. For jack pine, it was 51% and 33% for the same response variables. These results are a step toward models that could be used in sawing simulation software designed to estimate the internal properties of sawlogs and, as a result, better predict lumber and pulp chip quality.
Anti-inflammatory properties of kaempferol via its inhibition of aldosterone signaling and aldosterone-induced gene expression
Authors: Liu Zi-Kui , Xiao Hong-Bo , Fang Jun
Published: November 2013

Osteopontin (OPN), also called cytokine Eta-1, is a pro-inflammatory cytokine. Recent studies have shown that aldosterone increases OPN gene expression in endothelial cells. As a flavonoid compound, kaempferol has potent anti-inflammatory properties, but whether kaempferol regulates aldosterone signaling and aldosterone-induced gene expression is still unknown. Human umbilical vein endothelial cells (HUVECs) were pretreated with kaempferol (0, 1, 3, or 10 μmol/L) for 1 h prior to exposure to aldosterone (10−6 mol/L) for 24 h. Aldosterone induced generation of reactive oxygen species; OPN and cluster of differentiation 44 gene expression; phospho-p38 MAPK and NF-κB binding activity. The effect of aldosterone was abrogated by kaempferol and spironolactone (10−6 mol/L). The present results suggest that kaempferol exerts its anti-inflammatory properties via its inhibition of aldosterone signaling and aldosterone-induced gene expression in HUVECs.
G protein-coupled receptor 120 signaling regulates ghrelin secretion in vivo and in vitro
Authors: Gong Zhi , Yoshimura Makoto , Aizawa Sayaka , Kurotani Reiko , Zigman Jeffrey M. , Sakai Takafumi , Sakata Ichiro
Published: November 2013

Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor, is produced predominantly in the stomach. It has been reported that endogenous ghrelin levels are increased by fasting and decreased immediately after feeding and that fasting-induced ghrelin release is controlled by the sympathetic nervous system. However, the mechanisms of plasma ghrelin decrement after feeding are poorly understood. Here, we studied the control of ghrelin secretion using ghrelin-producing cell lines and found that these cells express high levels of mRNA encoding G-protein coupled receptor 120 (GPR120). Addition of GW-9508 (a GPR120 chemical agonist) and α-linolenic acid (a natural ligand for GPR120) inhibited the secretion of ghrelin by ∼50 and 70%, respectively. However, the expression levels of preproghrelin and ghrelin O-acyltransferase (GOAT) mRNAs were not influenced by GW-9508. In contrast, the expression levels of prohormone convertase 1 were decreased significantly by GW-9508 incubation. Moreover, we observed that the inhibitory effect of GW-9508 on ghrelin secretion was blocked by a small interfering RNA (siRNA) targeting the sequence of GPR120. Furthermore, pretreatment with GW-9508 blocked the effect of the norepinephrine (NE)-induced ghrelin elevation in ghrelin cell lines. In addition, we showed that GW-9508 inhibited ghrelin secretion via extracellular signal-regulated kinase activity in ghrelin cell lines. Finally, we found that GW-9508 decreased plasma ghrelin levels in mice. These results suggest that the decrease of ghrelin secretion after feeding is induced partially by long-chain fatty acids that act directly on gastric GPR120-expressing ghrelin cells.
Bovine β-defensin gene family: opportunities to improve animal health?
Authors: Meade K. G. , Cormican P. , Narciandi F. , Lloyd A. , O'Farrelly C.
Published: November 2013

Recent analysis of the bovine genome revealed an expanded suite of β-defensin genes that encode what are referred to as antimicrobial or host defense peptides (HDPs). Whereas primate genomes also encode α- and θ-defensins, the bovine genome contains only the β-defensin subfamily of HDPs. β-Defensins perform diverse functions that are critical to protection against pathogens but also in regulation of the immune response and reproduction. As the most comprehensively studied subclass of HDPs, β-defensins possess the widest taxonomic distribution, found in invertebrates as well as plants, indicating an ancient point of origin. Cross-species comparison of the genomic arrangement of β-defensin gene repertoire revealed them to vary in number among species presumably due to differences in pathogenic selective pressures but also genetic drift. β-Defensin genes exist in a single cluster in birds, but four gene clusters exist in dog, rat, mouse, and cow. In humans and chimpanzees, one of these clusters is split in two as a result of a primate-specific pericentric inversion producing five gene clusters. A cluster of β-defensin genes on bovine chromosome 13 has been recently characterized, and full genome sequencing has identified extensive gene copy number variation on chromosome 27. As a result, cattle have the most diverse repertoire of β-defensin genes so far identified, where four clusters contain at least 57 genes. This expansion of β-defensin HDPs may hold significant potential for combating infectious diseases and provides opportunities to harness their immunological and reproductive functions in commercial cattle populations.
Self-Nanoemulsifying Powder of Isotretinoin: Preparation and Characterization
Authors: Chavda Hitesh , Patel Jaimeen , Chavada Gordhan , Dave Shruti , Patel Ankini , Patel Chhagan
Published: November 2013

In the present investigation an attempt was made to enhance the solubility and dissolution of poorly soluble drug, isotretinoin, by formulating self-nanoemulsifying drug delivery system (SNEDDS). Liquid SNEDDSs were prepared using Transcutol P as oil, Tween 80 as surfactant, and PEG 400 as cosurfactant. Pseudoternary phase diagrams were constructed to identify the efficient self-nanoemulsification region. The formulation with 40% oil (Transcutol P) and 60% surfactant: cosurfactant (Tween 80: PEG 400) ratio of 1 : 1 was optimized based on evaluation parameters for droplet size analysis, self-emulsification capacity, zeta potential, and in vitro drug release performance. The optimized system contains mean droplet size of 36.60 nm and zeta potential (ζ) −26.73 mV. The optimized formulation A1 was adsorbed onto Fujicalin to produce solid SNEDDS, which exhibited good flow properties and preserved the self-emulsification properties of liquid SNEDDS. The differential scanning calorimetry, FT-IR studies of solid SNEDDS revealed transformation of isotretinoin into molecularly dissolved state in the liquid SNEDDS. In vitro dissolution profiles showed that dissolution rate of ISN from solid SNEDDS was significantly greater as compared to pure drug.
Clinical Epidemiology of Reduced Kidney Function among Elderly Male Fishing and Agricultural Population in Taipei, Taiwan
Authors: Kuo Chi-Mei , Chien Wu-Hsiung , Shen Hsi-Che , Hu Yi-Chun , Chen Yu-Fen , Tung Tao-Hsin
Published: November 2013

Purpose. To quantify the prevalence of and associated factors for chronic kidney disease (CKD) among male elderly fishing and agricultural population in Taipei, Taiwan.Methods. Subjects (n=2,766) aged 65 years and over voluntarily admitted to a teaching hospital for a physical checkup were collected in 2010. CKD was defined as an estimated glomerular filtration rate <60 mL/min/1.73 m2.Results. Among these subjects, the over prevalence of chronic kidney disease was 13.6% (95% CI: 12.3–14.9%). The age-specific prevalence of CKD in 65–74 years, 75–84 years, and ≥85 years was 8.2%, 19.1%, and 27.0%, respectively. From the multiple logistic regression, age (OR = 1.05, 95% CI: 1.02–1.09), hyperuricemia (OR = 2.94, 95% CI: 1.90–3.78), central obesity (OR = 1.17, 95% CI: 1.02–1.56), hyperglycemia (OR = 1.23, 95% CI: 1.11–1.67), hypertriglyceridemia (OR = 1.25, 95% CI: 1.08–1.66), and lower HDL-C (OR = 1.61, 95% CI: 1.23–1.92) were statistically significantly related to CKD. The presence of metabolic components (one or two versus none, OR = 1.10, 95% CI: 1.04–1.25; three or more versus none, OR = 2.12, 95% CI: 1.86–2.78) also appeared to be statistically significantly related to CKD after adjustment for other independent factors.Conclusion. Several clinical factors independently affect the development of CKD in the elderly male fishing and agricultural population.
Fault Detection Filter Design for Stochastic Systems with Mixed Time-Delays and Parameter Uncertainties
Authors: Hou Liyuan , Zhong Shouming , Zhu Hong , Zeng Yong , Shi Lin
Published: November 2013

This paper purposes the design of a fault detection filter for stochastic systems with mixed time-delays and parameter uncertainties. The main idea is to construct some new Lyapunov functional for the fault detection dynamics. A new robustly asymptotically stable criterion for the systems is derived through linear matrix inequality (LMI) by introducing a comprehensive different Lyapunov-Krasovskii functional. Then, the fault detection filter is designed in terms of linear matrix inequalities (LMIs) which can be easily checked in practice. At the same time, the error between the residual signal and the fault signal is made as small as possible. Finally, an example is given to illustrate the effectiveness and advantages of the proposed results.
A Giant Ureteral Stone without Underlying Anatomic or Metabolic Abnormalities: A Case Report
Authors: Sarikaya Selcuk , Resorlu Berkan , Ozyuvali Ekrem , Bozkurt Omer Faruk , Oguz Ural , Unsal Ali
Published: November 2013

A 28-year old man presented with left flank pain and dysuria. Plain abdominal film and computed tomography showed a left giant ureteral stone measuring 11.5 cm causing ureteral obstruction and other stones 2.5 cm in size in the lower pole of ipsilateral kidney and 7 mm in size in distal part of right ureter. A left ureterolithotomy was performed and then a double J stent was inserted into the ureter. The patient was discharged from the hospital 4 days postoperatively with no complications. Stone analysis was consistent with magnesium ammonium phosphate and calcium oxalate. Underlying anatomic or metabolic abnormalities were not detected. One month after surgery, right ureteral stone passed spontaneously, left renal stone moved to distal ureter, and it was removed by ureterolithotomy. Control intravenous urography and cystography demonstrated unobstructed bilateral ureter and the absence of vesicoureteral reflux.
The Synergistic Effects of Low Dose Fluorouracil and TRAIL on TRAIL-Resistant Human Gastric Adenocarcinoma AGS Cells
Authors: Zhu Hong , Huang Min , Ren Daoling , He Jianping , Zhao Fen , Yi Cheng , Huang Ying
Published: November 2013

The TNF-related apoptosis-inducing ligand (TRAIL) is a TNF family member which has been under intense focus because of its remarkable ability to induce apoptosis in malignant human cells while leaving normal cells unscathed. However, many cancer cells remain resistant to TRAIL. In this study, we had investigated the synergistic effects of low dose fluorouracil (5-Fu) and TRAIL on TRAIL-resistant human gastric adenocarcinoma AGS cells and explored the potential mechanisms. Cell viability was analyzed by sulforhodamine B (SRB) assay and the synergistic effects were evaluated by Jin’s formula and confirmed by both morphological changes under inverted microscope and flow cytometry. The expression of TRAIL-R1 (death receptor 4, DR4), TRAIL-R2 (DR5), TRAIL-R3 (decoy receptor, DcR1), TRAIL-R4 (DcR2), procaspase-3, procaspase-8, and procaspase-9 was detected by western blotting. Our results showed that there were significant synergistic effects of low dose 5-Fu and TRAIL on TRAIL-resistant AGS cells, and this effect was supposed to be mediated by decreasing DcR2 expression and increasing DR5 expression. The extrinsic and intrinsic apoptosis pathways were both activated. The data suggest that combined treatment of low dose 5-Fu and TRAIL can be an effective therapeutic approach for gastric adenocarcinoma.
Dynamic Ride Height Adjusting Controller of ECAS Vehicle with Random Road Disturbances
Authors: Xu Xing , Chen Long , Sun Liqin , Sun Xiaodong
Published: November 2013

The ride height control system is greatly affected by the random road excitation during the ride height adjusting of the driving condition. The structure of ride height adjusting system is first analyzed, and then the mathematical model of the ride height adjusting system with the random disturbance is established as a stochastic nonlinear system. This system is decoupled using the differential geometry theory and stabilized using the Variable Structure Control (VSC) technique. The designed ride height control system converges in probability to be asymptotically stable in the sliding motion band, and the desired control law is solved to ensure the stable adjustment of the ride height system. Simulation results show that the proposed stochastic VSC method is effective for the dynamic adjusting of the ride height. Finally, the semiphysical rig test illustrates the applicability of the proposed scheme.
Acupuncture in Practice: Investigating Acupuncturists’ Approach to Treating Infantile Colic
Authors: Landgren Kajsa
Published: November 2013

Infantile colic is common, but no safe and effective conventional treatment exists. The use of acupuncture has increased despite weak evidence. This practitioner survey explores and discusses how infantile colic is regarded and treated in Traditional Chinese Medicine (TCM). The study is based on personal communication with 24 acupuncturists from nine countries. These acupuncturists specialize in pediatric acupuncture and represent different styles of acupuncture. Their experiences are discussed and related to relevant books and articles. Informants claimed good results when treating infants with colic. The TCM patterns commonly described by informants matched the textbooks to a great extent. The most common syndromes were “stagnation of food” and “Spleen Qi Xu.” Regarding treatment, some informants followed the teachers’ and the textbook authors’ advice on differentiated treatment according to syndrome. The points used most often were LI4, ST36, and Sifeng. Other informants treated all infants alike in one single point, LI4. The results demonstrate the diversity of TCM. The use of acupuncture for infantile colic presents an interesting option, but further research is needed in order to optimize the effects and protect infants from unnecessary or less effective treatment.
On the Distributions of Subgraph Centralities in Complex Networks
Authors: Li Faxu , Wei Liang , Zhao Haixing , Hu Feng
Published: November 2013

Subgraph centrality measure characterizes the participation of each node in all subgraphs in a network. Smaller subgraphs are given more weight than large ones, which makes this measure appropriate for characterizing network motifs. This measure is better in being able to discriminate the nodes of a network than alternate measures. In this paper, the important issue of subgraph centrality distributions is investigated through theory-guided extensive numerical simulations, for three typical complex network models, namely, the ER random-graph networks, WS small-world networks, and BA scale-free networks. It is found that these three very different types of complex networks share some common features, particularly that the subgraph centrality distributions in increasing order are all insensitive to the network connectivity characteristics, and also found that the probability distributions of subgraph centrality of the ER and of the WS models both follow the gamma distribution, and the BA scale-free networks exhibit a power-law distribution with an exponential cutoff.
The Modified Parseval Equality of Sturm-Liouville Problems with Transmission Conditions
Authors: Bai Mudan , Sun Jiong , Yao Siqin
Published: November 2013

We consider the Sturm-Liouville (S-L) problems with very general transmission conditions on a finite interval. Firstly, we obtain the sufficient and necessary condition forλbeing an eigenvalue of the S-L problems by constructing the fundamental solutions of the problems and prove that the eigenvalues of the S-L problems are bounded below and are countably infinite. Furthermore, the asymptotic formulas of the eigenvalues and eigenfunctions of the S-L problems are obtained. Finally, we derive the eigenfunction expansion for Green's function of the S-L problems with transmission conditions and establish the modified Parseval equality in the associated Hilbert space.
The Study of Nebular Emission on Nearby Spiral Galaxies in the IFU Era
Authors: Rosales-Ortega Fernando Fabián
Published: November 2013

A new generation of wide-field emission-line surveys based on integral field units (IFU) is allowing us to obtain spatially resolved information of the gas-phase emission in nearby late-type galaxies, based on large samples of HII regions and full two-dimensional coverage. These observations are allowing us to discover and characterise abundance differentials between galactic substructures and new scaling relations with global physical properties. Here I review some highlights of our current studies employing this technique: (1) the case study of NGC 628, the largest galaxy ever sampled with an IFU; (2) a statistical approach to the abundance gradients of spiral galaxies, which indicates auniversalradial gradient for oxygen abundance; and (3) the discovery of a new scaling relation of HII regions in spiral galaxies, thelocalmass-metallicity relation of star-forming galaxies. The observational properties and constrains found in local galaxies using this new technique will allow us to interpret the gas-phase abundance of analogue high-z systems.
Application of Computational Intelligence in Order to Develop Hybrid Orbit Propagation Methods
Authors: Pérez Iván , San-Juan Juan Félix , San-Martín Montserrat , López-Ochoa Luis María
Published: November 2013

We present a new approach in astrodynamics and celestial mechanics fields, calledhybrid perturbation theory. A hybrid perturbation theory combines anintegrating technique, general perturbation theory or special perturbation theory or semianalytical method, with aforecasting technique, statistical time series model or computational intelligence method. This combination permits an increase in the accuracy of the integrating technique, through the modeling of higher-order terms and other external forces not considered in the integrating technique. In this paper, neural networks have been used as time series forecasters in order to help two economic general perturbation theories describe the motion of an orbiter only perturbed by the Earth’s oblateness.
SILAR‐Based Application of Various Nanopillars on GaN‐Based LED to Enhance Light‐Extraction Efficiency
Authors: Shei S. C.
Published: November 2013

We reported the various nanopillars on GaN‐based LED to enhance light‐extraction efficiency prepared by successive ionic layer adsorption and reaction method (SILAR). Indium tin oxide (ITO) with thickness of 1 μm as transparent contact layer was grown to improve the electrical characteristics of the LEDs, including series resistance and operating voltage. SILAR‐deposition ZnO nanoparticles on SiO2 were used as etching nanomasks. Multiple nanopillars were simultaneously formed on overall surfaces of ITO p‐ and n‐GaN by ICP etching. The proposed GaN‐based LEDs with nanopillars increase light output power by 7%–20.3% (at 20 mA) over that of regular GaN‐based LEDs. The difference in light output power can be attributed to differences in materials and shapes of nanopillars, resulting in a reduction in Fresnel reflection by the roughened surface of GaN‐based LEDs.
Risk of Preterm Delivery Associated with Prior Treatment of Cervical Precancerous Lesion according to the Depth of the Cone
Authors: Berretta Roberto , Gizzo Salvatore , Dall’Asta Andrea , Mazzone Eleonora , Monica Michela , Franchi Laura , Peri Francesca , Patrelli Tito Silvio , Bacchi Modena Alberto
Published: November 2013

The aim of this study was to evaluate the impact of the surgical excisional procedures for cervical intraepithelial neoplasia (CIN) treatment both on subsequent fertility (cervical factor) and pregnancy complication (risk of spontaneous preterm delivery). We retrospectively analyzed 236 fertile women who underwent conization for CIN. We included in the study 47 patients who carried on pregnancy and delivered a viable fetus. Patients were asked about postconization pregnancies, obstetrical outcomes, and a possible diagnosis of secondary infertility caused by cervical stenosis. We evaluated the depth of surgical excision, the timing between cervical conization and subsequent pregnancies, surgical technique, and maternal age at delivery. We recorded 47 deliveries, 10 cases of preterm delivery; 8 of them were spontaneous. The depth of surgical excision showed a statistically significant inverse correlation with gestational age at birth. The risk of spontaneous preterm delivery increased when conization depth exceeded a cut-off value of 1.5 cm. Our data do not demonstrated a relation between conization and infertility due to cervical stenosis.