bluuebunny/crossref_metadata_2025 huggingface dataset:
Strain Rate Calculation Approach in Environmental Fatigue Evaluations
Authors: Gray Mark A. , Salac Matthew C. , Roarty David H. , Lyles Cranford E.
Published: November 2013

Fatigue usage factor evaluations including the effects of reactor water environment have been performed in numerous nuclear plant license renewal efforts. A large number of these evaluations have used the environmental fatigue penalty factor, Fen, approach prescribed in various regulatory documents. The Fen equations require input of strain rate, but the prescribing documents do not provide methodology or criteria for the quantification of the strain rate to be input. As a result, numerous approaches have been offered and studied. This paper presents an approach used by Westinghouse to include strain rate in an automated calculation of Fen based on the modified rate approach (MRA) to integrated strain rate applications. The starting point of the approach is ASME Code Section III NB-3200 fatigue analysis. With environmental fatigue evaluations in new plant designs now emerging in ASME Code criteria, strain rate considerations remain part of the discussion. The intent of this paper is to provide further insight into this process.
Ultrasonic Measurement of Thick-Walled Pipe Diameter Changes
Authors: Szelążek Jacek , Gutkiewicz Piotr , Grzywna Paweł , Mackiewicz Sławomir
Published: November 2013

Thick-walled, main stream pipelines are key elements in many power and chemical plants. Operating for a long time in high temperature and subjected to internal pressure such pipes are subjected to creep resulting in material degradation and strain. The most common method of pipe state evaluation is pipe diameter monitoring. Usually such measurements are performed with micrometer gauge in locations where special “pips” were earlier installed. Other methods are also tested to monitor creep progress like various temperature-resistance strain gauges or eddy current sensors. The paper examines a new ultrasonic technique to evaluate thick-walled pipe diameter changes. Pipe diameter evaluation is based on time of flight of bulk ultrasonic waves propagating in circumferential direction along the polygon, reflecting on the pipe external surface only. Presented are results of experiments performed on 100 mm diameter pipe subjected to internal pressure to generate small diameter changes and on 273 mm diameter and 40 mm wall thickness pipe section. Measurements were performed with longitudinal, shear SV and shear SH waves. Described are advantages and disadvantages of various ultrasonic wave types for pipe diameter evaluation in practice. Discussed is the influence of residual stresses and temperature on accuracy of pipe diameter evaluation with proposed technique. Shear SV wave was chosen as the most easily applicable ultrasonic wave on thick-walled tubes.
Measurement of Tool-Workpiece Interface Temperature Distribution in Friction Stir Welding
Authors: Fehrenbacher Axel , Schmale Joshua R. , Zinn Michael R. , Pfefferkorn Frank E.
Published: November 2013

The objective of this work is to develop an improved temperature measurement system for friction stir welding (FSW). FSW is a solid-state joining process enabling welds with excellent metallurgical and mechanical properties, as well as significant energy consumption and cost savings compared to traditional fusion welding processes. The measurement of temperatures during FSW is needed for process monitoring, heat transfer model verification and process control, but current methods have limitations due to their restricted spatial and temporal resolution. Previous work showed that temperatures at the tool shoulder-workpiece interface can be measured and utilized for closed-loop control of temperature. Adding an additional thermocouple at the tool pin-workpiece interface and performing a calibration of the measurement to gain better insight into the temperature distribution in the weld zone improved the method. Both thermocouples were placed in through holes right at the interface of tool so that the sheaths are in direct contact with the workpiece material. This measurement strategy reveals dynamic temperature variations at the shoulder and the pin within a single rotation of the tool in real-time. It was found that the highest temperatures are at the shoulder interface between the advancing side and the trailing edge of the tool, closer to the advancing side. The temperature distribution was mostly affected by travel speed and the temperature difference within one tool rotation was found to be between 10 °C and 50 °C, depending on the process parameters. The dynamic temperature measurements obtained with the current system are of unmatched resolution, fast, and reliable and are likely to be of interest for both fundamental studies and process control of FSW.
Hybrid Power Generation Plant for CO2 Capture
Authors: Deng Shimin , Hynes Rory , Drover Brian
Published: November 2013

In this paper, the issues and challenges of capturing CO2 from a pulverized coal (PC) power plant have been summarized and assessed and a hybrid power generation configuration is developed, which features a gas-turbine cogeneration unit supplying steam for stripping CO2, thereby decoupling the CO2 capture from the steam cycle of PC units. The hybrid power generation cases are modeled by using GTProTM and SteamProTM. The performance of the hybrid power plant is compared with the base case that uses extraction from the steam cycle. Retrofitting existing power plants by this hybrid concept is also assessed; performance comparison and economic analysis indicate that this kind of retrofitting is attractive to utilities with PC power generation fleet.
Effect of Variable Properties Within a Boundary Layer With Large Freestream-to-Wall Temperature Differences
Authors: Greiner Nathan J. , Polanka Marc D. , Rutledge James L. , Robertson Jacob R.
Published: November 2013

Modern gas-turbine engines are characterized by high core-flow temperatures and significantly lower turbine-surface temperatures. This can lead to large property variations within the boundary layers on the turbine surfaces. However, cooling of turbines is generally studied near room temperature, where property variation within the boundary layer is negligible. The present study first employs computational fluid dynamics to validate two methods for quantifying the effect of variable properties in a boundary layer: the reference temperature method and the temperature ratio method. The computational results are then used to expand the generality of the temperature ratio method by proposing a slight modification. Next, these methods are used to quantify the effect of variable properties within a boundary layer on measurement techniques, which assume constant properties. Both low-temperature flows near ambient and high-temperature flows with a freestream temperature of 1600 K are considered under both laminar and turbulent conditions. The results show that variable properties have little effect on laminar flows at any temperature or turbulent flows at low temperatures such that constant property methods can be validly employed. However, variable properties are seen to have a profound effect on turbulent flows at high temperatures. For the high-temperature turbulent flow considered, the constant property methods are found to overpredict the convective heat transfer coefficient by up to 54.7% and underpredict the adiabatic wall temperature by up to 209 K. Utilizing the variable property techniques, a new method for measuring the adiabatic wall temperature and variable property heat-transfer coefficient is proposed for variable property flows.
Magnetohydrodynamic Boundary Layer Flow and Heat Transfer of a Nanofluid Over Non-Isothermal Stretching Sheet
Authors: Ibrahim Wubshet , Shanker B.
Published: November 2013

The boundary-layer flow and heat transfer over a non-isothermal stretching sheet in a nanofluid with the effect of magnetic field and thermal radiation have been investigated. The transport equations used for the analysis include the effect of Brownian motion and thermophoresis. The solution for the temperature and nanoparticle concentration depends on six parameters, viz., thermal radiation parameter R, Prandtl number Pr, Lewis number Le, Brownian motion Nb, and the thermophoresis parameter Nt. Similarity transformation is used to convert the governing nonlinear boundary-layer equations into coupled higher order nonlinear ordinary differential equations. These equations were numerically solved using a fourth-order Runge–Kutta method with shooting technique. The analysis has been carried out for two different cases, namely prescribed surface temperature (PST) and prescribed heat flux (PHF) to see the effects of governing parameters for various physical conditions. Numerical results are obtained for distribution of velocity, temperature and concentration, for both cases i.e., prescribed surface temperature and prescribed heat flux, as well as local Nusselt number and Sherwood number. The results indicate that the local Nusselt number decreases with an increase in both Brownian motion parameter Nb and thermophoresis parameter Nt. However, the local Sherwood number increases with an increase in both thermophoresis parameter Nt and Lewis number Le. Besides, it is found that the surface temperature increases with an increase in the Lewis number Le for prescribed heat flux case. A comparison with the previous studies available in the literature has been done and we found an excellent agreement with it.
Unsteady Laminar Forced-Convective Tube Flow Under Dynamic Time-Dependent Heat Flux
Authors: Fakoor-Pakdaman M. , Andisheh-Tadbir Mehdi , Bahrami Majid
Published: November 2013

A new all-time model is developed to predict transient laminar forced convection heat transfer inside a circular tube under arbitrary time-dependent heat flux. Slug flow (SF) condition is assumed for the velocity profile inside the tube. The solution to the time-dependent energy equation for a step heat flux boundary condition is generalized for arbitrary time variations in surface heat flux using a Duhamel's integral technique. A cyclic time-dependent heat flux is considered and new compact closed-form relationships are proposed to predict (i) fluid temperature distribution inside the tube, (ii) fluid bulk temperature and (iii) the Nusselt number. A new definition, cyclic fully developed Nusselt number, is introduced and it is shown that in the thermally fully developed region the Nusselt number is not a function of axial location, but it varies with time and the angular frequency of the imposed heat flux. Optimum conditions are found which maximize the heat transfer rate of the unsteady laminar forced-convective tube flow. We also performed an independent numerical simulation using ansys fluent to validate the present analytical model. The comparison between the numerical and the present analytical model shows great agreement; a maximum relative difference less than 5.3%.
Computational Fluid Dynamics and Optimization of Flow and Heat Transfer in Coiled Tube-in-Tube Heat Exchangers Under Turbulent Flow Conditions
Authors: Aly Wael I. A.
Published: November 2013

The present computational fluid dynamics (CFD) study was performed to investigate the 3D turbulent flow and heat transfer of coiled tube-in-tube heat exchangers (CTITHEs). The realizable k-ε model with enhanced wall treatment was used to simulate the turbulent flow and heat transfer in the heat exchangers. Temperature dependent thermophysical properties of water were used and heat exchangers are analyzed considering conjugate heat transfer from hot fluid in the inner-coiled tube to cold fluid in the annulus region. After simulations, Taguchi method was used for finding the optimum condition for some design parameters in the range of coil diameter from 0.18 to 0.3 m, tube and annulus flow rates from 2 to 4 and 10 to 20 LPM, respectively. Results show that the Gnielinski correlation used extensively for predicting Nusselt number for turbulent flow in ducts can be used to predict Nusselt number for both inner-coiled tube and annular coiled tube using the friction factor correlation for helical tubes of Mishra and Gupta. Contribution ratio obtained by Taguchi method shows that annulus side flow rate, tube side flow rate, coil diameter, and flow configuration are the most important design parameters in coiled tube-in-tube heat exchangers, respectively.
Experimental and Numerical Investigation of the Flow Field at Radial Holes in High-Speed Rotating Shafts
Authors: Sousek Jan , Riedmüller Daniel , Pfitzner Michael
Published: November 2013

Rotating and stationary orifices are used within the secondary air system to transport sealing/cooling air to its consumers. This paper reports on measurements of the discharge coefficient of rotating radial holes since their aerodynamical behavior is different from that of axial or stationary holes due to the presence of centrifugal and Coriolis forces. A test rig containing two independently rotating shafts was designed in order to investigate the flow phenomena and the discharge behavior of these orifices. The required air mass flow is delivered by a screw compressor and can be independently regulated to supply the inner and outer annular passages of the test rig. It allows for measurements of the discharge coefficient with cross flow and co- and counter-rotating shafts with centrifugal and centripetal flow through the rotating holes. On the outer shaft, absolute and differential pressures and temperatures in the rotating frame of reference are measured via a telemetry system. Measurements of the discharge coefficient for sharp-edged and rounded shaft inserts at a variety of different flow conditions and with swirl added to the air upstream of the orifice are presented. Furthermore, experiments were conducted to quantify the influence of the inner shaft (nonrotating and rotating) on the discharge behavior of orifices in the outer shaft. To complement the data acquired from the experiments and to obtain a better understanding of the flow field near the rotating holes numerical flow simulations were also performed.
Buckling of High-Strength Steel Cylinders Under Cyclic Bending in the Inelastic Range1
Authors: Varelis George E. , Karamanos Spyros A.
Published: November 2013

The present paper examines the structural behavior of elongated steel hollow cylinders, referred to as tubes or pipes, subjected to large cyclic bending, through a rigorous finite element simulation. The bent cylinders exhibit cross-sectional distortion, in the form of ovalization, combined with excessive plastic deformations. Those deformations grow under repeated loading and may lead to structural instability in the form of local buckling (wrinkling) and, eventually, failure of the loaded member. The study focuses on relatively thick-walled seamless cylindrical members made of high-strength steel, which exhibit local buckling in the plastic range of the steel material. The analysis is conducted using advanced nonlinear finite element models capable of describing both geometrical and material nonlinearities. A cyclic plasticity model that adopts the “bounding surface” concept is employed. The material model is calibrated through special-purpose material testing, and implemented within ABAQUS, using a user-subroutine. The finite element model is validated by comparison with two experiments on high-strength steel tubular members. Special emphasis is given on the increase of ovalization and the gradual development of small-amplitude initial wrinkles with repeated loading cycles. A parametric numerical study is conducted, aimed at determining the effects of initial wrinkles on plastic buckling performance.
An Augmented State Formulation for Modeling and Analysis of Multibody Distributed Dynamic Systems
Authors: Noh K. , Yang B.
Published: November 2013

Multibody distributed dynamic systems are seen in many engineering applications. Developed in this investigation is a new analytical method for a class of branched multibody distributed systems, which is called the augmented distributed transfer function (DTFM). This method adopts an augmented state formulation to describe the interactions among multiple distributed and lumped bodies, which resolves the problems with conventional transfer function methods in modeling and analysis of multibody distributed systems. As can be seen, the augmented DTFM, without the need for orthogonal system eigenfunctions, produces exact and closed-form solutions of various dynamic problems, in both frequency and time domains.
Gas Turbine Engine Health Management: Past, Present, and Future Trends
Authors: Volponi Allan J.
Published: November 2013

Engine diagnostic practices are as old as the gas turbine itself. Monitoring and analysis methods have progressed in sophistication over the past six decades as the gas turbine evolved in form and complexity. While much of what will be presented here may equally apply to both stationary power plants and aeroengines, the emphasis will be on aeropropulsion. Beginning with primarily empirical methods centered on monitoring the mechanical integrity of the machine, the evolution of engine diagnostics has benefited from advances in sensing, electronic monitoring devices, increased fidelity in engine modeling, and analytical methods. The primary motivation in this development is, not surprisingly, cost. The ever increasing cost of fuel, engine prices, spare parts, maintenance, and overhaul all contribute to the cost of an engine over its entire life cycle. Diagnostics can be viewed as a means to mitigate risk in decisions that impact operational integrity. This can have a profound impact on safety, such as in-flight shutdowns (IFSD) for aero applications, (outages for land-based applications) and economic impact caused by unscheduled engine removals (UERs), part life, maintenance and overhaul, and the overall logistics of maintaining an aircraft fleet or power generation plants. This paper will review some of the methods used in the preceding decades to address these issues, their evolution to current practices, and some future trends. While several different monitoring and diagnostic systems will be addressed, the emphasis in this paper will be centered on those dealing with the aerothermodynamic performance of the engine.
Parametric Optimization of Unsteady End Wall Blowing on a Highly Loaded Low-Pressure Turbine
Authors: Benton Stuart I. , Bernardini Chiara , Bons Jeffrey P. , Sondergaard Rolf
Published: November 2013

Efforts to reduce blade count and avoid boundary layer separation have led to low-pressure turbine airfoils with significant increases in loading as well as front-loaded pressure distributions. These features have been independently shown to increase losses within the secondary flow field at the end wall. Compound angle blowing from discrete jets on the blade suction surface near the end wall has been shown to be effective in reducing these increased losses and enabling the efficient use of highly loaded blade designs. In this study, experiments are performed on the front loaded L2F low-pressure turbine airfoil in a linear cascade. The required mass flow is reduced by decreasing the hole count from previous configurations and from the introduction of unsteady blowing. The effects of pulsing frequency and duty cycle are investigated using phase-locked stereo particle image velocimetry to demonstrate the large scale movement and hysteresis behavior of the passage vortex interacting with the pulsed jets. Total pressure loss contours at the cascade outlet demonstrate that the efficiency benefit is maintained with the use of unsteady forcing.
Robust Control Based on Generalized Predictive Control Applied to Switched Reluctance Motor Current Loop
Authors: Torrico Bismark C. , Almeida Rômulo N. de C. , dos Reis Laurinda L. N. , Silva Wellington A. , Pontes Ricardo S. T.
Published: November 2013

This paper proposes a robust control based on generalized predictive control (GPC) applied to the current control loop for a switched reluctance motor (SRM) drive. The proposed controller has two degrees of freedom where the setpoint tracking is decoupled from the load disturbance rejection at the nominal case. In addition a filter design is proposed in order to achieve good relationship among robustness, load disturbance rejection, and noise attenuation. Simulation and real experimental results are shown to illustrate the controller performance.
Scaling the Speed Limitations for Axial-Piston Swash-Plate Type Hydrostatic Machines
Authors: Manring Noah D. , Mehta Viral S. , Nelson Bryan E. , Graf Kevin J. , Kuehn Jeff L.
Published: November 2013

This paper proposes a scaling law for estimating the speed limitations for a family of axial-piston swash-plate type hydrostatic machines. The speed limitations for this machine are considered from three mechanical perspectives: (1) cylinder-block tipping, (2) cylinder-block filling, and (3) slipper-tipping. As shown in the results of this research, each speed limitation is scaled by the inverse of the cube root of the volumetric displacement for the new machine. In other words, small machines are shown to have a higher speed capacity than larger machines. By scaling a baseline machine using the scale laws that are presented here, a new machine may be produced that obeys a simple rule related only to the volumetric displacement of the new machine. Serendipitously, and perhaps most usefully, all three speed limitations obey the same rule! The speed limitations that are derived in this research are compared to existing industry data of currently scaled products and it is shown that the proposed scale laws correspond well with this data.
On-Board Fuel Property Identification Method Based on High-Pressure Common Rail Pressure Signal
Authors: Zhao Junfeng , Wang Junmin
Published: November 2013

This paper investigates the impact of fuel property variations on the common rail pressure fluctuation in high-pressure common rail (HPCR) system and explores the possibility of identifying the fuel types based on the measurement of rail pressure for internal combustion engines. Fluid transients, particularly the water hammer effect in a HPCR system, are discussed and the 1D governing equations are given. A typical HPCR system model is developed in GT-Suite with the injectors, three-plunger high-pressure pump, and pressure control valve being modeled in a relatively high level of detail. Four different fuels including gasoline, ethanol, diesel, and biodiesel are modeled and their properties including density, bulk modulus, and acoustic wave speed are validated against data in the literature. Simulation results are obtained under different conditions with variable rail pressures and engine speeds. To reduce the excessive rail pressure oscillation caused by multiple injections, only four main-injections are enabled in each engine revolution. The results show that the natural frequency of a common rail varies with the type of fuel filled in it. By applying the fast Fourier transform (FFT) to the pressure signal, the differences of fuel properties can be revealed in the frequency domain. The experiment validation is conducted on a medium-duty diesel engine, which is equipped with a typical HPCR system and piezo-electric injectors. Tests results are given for both pure No. 2 diesel and pure soybean biodiesel at different rail pressure levels and different engine speeds. This approach is proved to be potentially useful for fuel property identification of gasoline-ethanol or diesel-biodiesel blends on internal combustion engines.
Integrated Robust Optimal Design Using Bilinear Matrix Inequality Approach Via Sensitivity Minimization
Authors: Tulpule Punit J. , Kelkar Atul G.
Published: November 2013

A novel integrated robust control synthesis methodology is presented here which combines a traditional sensitivity theory with relatively new advancements in bilinear matrix inequality (BMI) constrained optimization problems. The proposed methodology is demonstrated using a numerical example of integrated control design problem for combine harvester header linkage. The integrated design methodology presented is compared with a traditional sequential design method and the results show that the proposed methodology provides a viable alternative for robust controller synthesis and often times offers even a better performance than competing methods.
Load Position Estimation for Crane Anti-Sway Control Systems
Authors: Schaper Ulf , Sawodny Oliver , Zeitz Michael , Schneider Klaus
Published: November 2013

A rising number of modern cranes are equipped with anti-sway control systems to facilitate crane operation, improve positioning accuracy, and increase turnover. Commonly, these industrial crane control systems require pendulum state information for feedback control. Therefore, a pendulum sway sensor (e.g., a rope-mounted gyroscope) and a signal processing algorithm are required. Such a signal processing algorithm needs to filter out disturbances from both the sensor and the crane, e.g., signal noise and string oscillations of a long rope. Typically, these signal processing algorithms require the knowledge of the acceleration of the rope suspension point. This acceleration signal is often estimated from drive models. When drive models are uncertain, the pendulum state estimation accuracy suffers from drive model inaccuracy. In this contribution, an improved estimation algorithm is presented which estimates the load position without relying on the rope suspension point acceleration. The developed Extended Kalman Filter is implemented on a Liebherr mobile harbor crane and its effectiveness is validated with multiple test rides and GPS load position reference measurements.
Cooperative Global Robust Output Regulation for Nonlinear Multi-Agent Systems in Output Feedback Form
Authors: Dong Yi , Huang Jie
Published: November 2013

In this paper, we consider the global robust output regulation problem for a class of nonlinear multi-agent systems by distributed output feedback control. We first show that the problem can be converted into the global stabilization problem of a class of multi-input, multi-output nonlinear systems called augmented system. Then, we further show that, under a set of standard assumptions, the augmented system can be globally stabilized by a distributed output feedback control law. Finally, we apply our approach to solve a leader-following synchronization problem for a group of Lorenz multi-agent systems.
An Experimental Investigation of Turbulent Water Flow in Concentric Annulus Using Particle Image Velocimetry Technique
Authors: Rodriguez-Corredor F. E. , Bizhani Majid , Ashrafuzzaman Mohammad , Kuru Ergun
Published: November 2013

Fully developed turbulent flow of water through a horizontal flow loop with concentric annular geometry was investigated using high resolution particle image velocimetry (PIV). Reynolds number range varied from 17,700 to 66,900. Axial mean velocity profile was found to be following the universal wall law (u+ = y+) in the viscous sublayer (y+ < 10) and log law away from the wall (y+> 30). Radial position of zero shear stress and maximum velocity were found to be slightly different (2%). Root mean square values of velocity fluctuations velocity, Reynolds stresses, vorticity, and turbulent kinetic energy budget were also analyzed.
Acoustic Source Characterization for Prediction of Medium Speed Diesel Engine Exhaust Noise
Authors: Hynninen Antti , Åbom Mats
Published: November 2013

To achieve reliable results when simulating the acoustics of the internal combustion engine (IC-engine) exhaust system and its components, the source characteristics of the engine must be known. In the low frequency range only plane waves propagate and then one-port source data can be determined using, for example, the acoustic multiload method. For the medium speed IC-engines used in power plants and ships, the exhaust duct noise often needs to be analyzed up to 10 kHz, i.e., far beyond the plane wave range, and it is then more appropriate to use acoustic power to characterize the source. This power should ideally be measured under reflection-free conditions in the exhaust duct. The results from an earlier study showed that a suitable way to characterize the source for any frequency is to determine the in-duct sound power by extending the plane wave formulation with frequency band power weighting factors. The aim of this study is to apply this high frequency range method in situ to a real test engine. Another aim is to define, theoretically, how to combine the source data in the low frequency plane wave range with those in the high frequency nonplane wave range using a source sound power formulation.
The Missing Mountain Water: Slower Westerlies Decrease Orographic Enhancement in the Pacific Northwest USA
Authors: Luce C. H. , Abatzoglou J. T. , Holden Z. A.
Published: November 2013

Up and Down

Climate change is expected to have significant impacts on Earth's hydrological cycle, owing to changes, for example, in air temperature, weather patterns, and land surface evaporation. In the Pacific Northwest of the United States, decreases in stream flow have been attributed to increased temperatures.

Luce
et al.

(p.
1360
, published online 29 November) show that these changes in stream flow are not likely to have been caused by temperature change, however, but rather by decreasing precipitation in the mountains where the streams originate.
Drosophila
Life Span and Physiology Are Modulated by Sexual Perception and Reward
Authors: Gendron Christi M. , Kuo Tsung-Han , Harvanek Zachary M. , Chung Brian Y. , Yew Joanne Y. , Dierick Herman A. , Pletcher Scott D.
Published: November 2013

Battle of the Sexes

In many species, males compete with one another to propagate their own DNA, often to the detriment of females (see the Perspective by
Promislow and Kaeberlein
).
Shi and Murphy
(p.
536
, published online 19 December) discovered that mating in
Caenorhabditis
species causes mothers to shrink and die soon after they have ceased producing progeny. Males appear to hijack the longevity and stress resistance pathways normally employed by the mothers to slow reproduction and somatic aging in times of stress.

Maures
et al.

(p.
541
, published online 29 November) explored why the presence of abundant mating-competent males causes a decrease in the life span of nematodes of the opposite sex and found that a secreted substance, possibly a pheromone, reproduced the effect of the males when transferred in the culture medium. Detection of pheromones from a female fruit fly is enough to cause changes in metabolism, reduce resistance to starvation, and shorten the life span of male flies.

Gendron
et al.

(p.
544
, published online 29 November) report that the signals from the female appear to be recognized by sensory receptors on the legs of male flies.
Males Shorten the Life Span of
C. elegans
Hermaphrodites via Secreted Compounds
Authors: Maures Travis J. , Booth Lauren N. , Benayoun Bérénice A. , Izrayelit Yevgeniy , Schroeder Frank C. , Brunet Anne
Published: November 2013

Battle of the Sexes

In many species, males compete with one another to propagate their own DNA, often to the detriment of females (see the Perspective by
Promislow and Kaeberlein
).
Shi and Murphy
(p.
536
, published online 19 December) discovered that mating in
Caenorhabditis
species causes mothers to shrink and die soon after they have ceased producing progeny. Males appear to hijack the longevity and stress resistance pathways normally employed by the mothers to slow reproduction and somatic aging in times of stress.

Maures
et al.

(p.
541
, published online 29 November) explored why the presence of abundant mating-competent males causes a decrease in the life span of nematodes of the opposite sex and found that a secreted substance, possibly a pheromone, reproduced the effect of the males when transferred in the culture medium. Detection of pheromones from a female fruit fly is enough to cause changes in metabolism, reduce resistance to starvation, and shorten the life span of male flies.

Gendron
et al.

(p.
544
, published online 29 November) report that the signals from the female appear to be recognized by sensory receptors on the legs of male flies.
Lenalidomide Causes Selective Degradation of IKZF1 and IKZF3 in Multiple Myeloma Cells
Authors: Krönke Jan , Udeshi Namrata D. , Narla Anupama , Grauman Peter , Hurst Slater N. , McConkey Marie , Svinkina Tanya , Heckl Dirk , Comer Eamon , Li Xiaoyu , Ciarlo Christie , Hartman Emily , Munshi Nikhil , Schenone Monica , Schreiber Stuart L. , Carr Steven A. , Ebert Benjamin L.
Published: November 2013

Drug With a (Re)Purpose

Thalidomide, once infamous for its deleterious effects on fetal development, has re-emerged as a drug of great interest because of its beneficial immunomodulatory effects. A derivative drug called lenalidomide significantly extends the survival of patients with multiple myeloma, but the molecular mechanisms underlying its efficacy remain unclear (see the Perspective by

Stewart

). Building on a previous observation that thalidomide binds to cereblon, a ubiquitin ligase,

Lu
et al.

(p.
305
, published online 28 November) and

Krönke
et al.

(p.
301
, published online 28 November) show that in the presence of lenalidomide, cereblon selectively targets two B cell transcription factors (Ikaros family members, IKZF1 and IKZF3) for degradation. In myeloma cell lines and patient cells, down-regulation of IKZF1 and IKZF3 was necessary and sufficient for the drug's anticancer activity. Thus, lenalidomide may act, at least in part, by “grepurposing” a ubiquitin ligase.
Parental discussion of G6PD deficiency and child health: implications for clinical practice
Authors: Guan Yue , Roter Debra L , Huang Aichu , Erby Lori A H , Chien Yin-Hsiu , Hwu Wuh-Liang
Published: November 2013

Objective

Parents are encouraged to discuss self-care with children affected by G6PD deficiency; however, little is known about the extent or impact of these discussions on the physical and psychosocial health of these children. The purpose of this study was to examine the nature of parental–child discussions of G6PD deficiency self-care and their relationship to child health.

Methods

A quantitative cross-sectional survey of 178 Taiwanese parents of children with G6PD deficiency was conducted. The extent of parental–child self-care discussions was assessed in regards to coverage of nine key topics. Parent's G6PD deficiency status, knowledge of haemolytic anaemia symptoms and reported G6PD deficiency education from providers were examined as correlates of parental discussion. Child health was assessed with the child health questionnaire-parent form (Chinese version) and a 13-item haemolytic anaemia symptom list.

Results

Self-care discussions were positively correlated with parental G6PD deficiency status (β=2.08, p=0.03), accurate identification of haemolytic anaemia symptoms (β=0.18, p=0.01), the thoroughness and clarity of patient education (β=0.14, p<0.001) and child age (β=1.04, p<0.001). Among children reported to have experienced significant symptoms of acute haemolytic anaemia (35%), the extent of self-care discussions was positively associated with reported physical and psychosocial child health (β=1.18, p<0.001).

Conclusions

Parental–child G6PD deficiency self-care discussions are associated with better child health, and parental involvement in these discussions is facilitated by the thoroughness and clarity of patient education received from providers.
The association between cytokines and insulin sensitivity in Iraqi immigrants and native Swedes
Authors: Memon Ashfaque A , Sundquist Jan , Wang Xiao , Palmér Karolina , Sundquist Kristina , Bennet Louise
Published: November 2013

Objectives

To investigate the associations between cytokines and insulin sensitivity in Swedish residents born in Iraq and Swedish residents born in Sweden.

Design

Cross-sectional study.

Settings

Iraqi and Swedish origin residents of Rosengård area of Malmö, aged 45–65 years, were randomly selected from the census register.

Participants/methods

194 (Iraqi, n=107; Swedish, n=87) participants agreed to participate in the study. Nineteen participants dropped out (Iraqi, n=11; Swedish, n=8). Participants who had already been diagnosed with type 2 diabetes mellitus (T2DM), those who could not participate in an oral glucose tolerance test and those who had a cold/fever at the time of blood sampling were excluded. In total, serum samples from 135 individuals of Swedish (n=62) and Iraqi (n=73) origin were included. Serum concentrations of a panel of 10 cytokines, comprising interleukin (IL)-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12 (p70), IL-13, interferon-γ and tumour necrosis factor-α were analysed by Luminex multiplex assay.

Results

In the whole study population, levels of all tested cytokines were inversely associated with insulin sensitivity index (ISI), independent of age, sex, body mass index (BMI), sedentary lifestyle and family history of T2DM (p ≤ 0.05). Interestingly, stratification of the study population according to country of birth showed a significant inverse association between all tested cytokines and ISI in the Iraqi-born population (p ≤ 0.01). The association was independent of age, sex, BMI, sedentary lifestyle and family history of T2DM. In contrast, with the exception for IL-6 (p=0.05), no other tested cytokine was found to be significantly associated with ISI in the Swedish-born population (p≥0.05).

Conclusions

Our results show an association between cytokines and ISI in the Iraqi-born population but not in the Swedish-born population.
Mindfulness online: an evaluation of the feasibility of a web-based mindfulness course for stress, anxiety and depression
Authors: Krusche Adele , Cyhlarova Eva , Williams J Mark G
Published: November 2013

Objectives

Face-to-face mindfulness interventions have been shown to significantly decrease perceived stress, anxiety and depression and research is beginning to show similar benefits for such courses delivered via the internet. We investigated the feasibility and effectiveness of an online mindfulness course for perceived stress, anxiety and depression.

Design

A follow-up investigation of an online mindfulness course. Previous research examining the change in perceived stress showed promising results. Measures of anxiety and depression were added to the online mindfulness course and these were investigated as well as perceived stress using a new, larger sample.

Participants

Participants (N=273) were self-referrals to the online course who completed the outcome measure immediately before the course, upon course completion and at 1 month follow-up.

Intervention

The programme consists of 10 sessions, guided meditation videos and automated emails, with elements of Mindfulness-Based Stress Reduction and Mindfulness-Based Cognitive Therapy, completed at a pace to suit the individual (minimum length 4 weeks).

Primary and secondary outcome measures

The Perceived Stress Scale, the Generalised Anxiety Disorder Assessment-7 and the Patient Health Questionnaire-9 (for depression). Mindfulness practice was self-reported at automated time points upon login, once the exercises and sessions for each week were completed.

Results

Perceived stress, anxiety and depression significantly decreased at course completion and further decreased at 1 month follow-up, with effect sizes comparable to those found with face-to-face and other online mindfulness courses and to other types of intervention, such as cognitive behavioural therapy for stress. The amount of meditation practice reported did affect outcome when controlling for baseline severity.

Conclusions

The online mindfulness course appears to be an acceptable, accessible intervention which reduces stress, anxiety and depression. However, there is no control comparison and future research is required to assess the effects of the course for different samples.
The relationship between suicidal ideation and symptoms of depression in Japanese workers: a cross-sectional study
Authors: Takeuchi Takeaki , Nakao Mutsuhiro
Published: November 2013

Objectives

The prevalence of suicidal ideation and predictors for suicidal ideation among Japanese workers is unknown, although a previous study reported a 30% prevalence rate of suicidal ideation in a psychosomatic clinical setting. Hence, we evaluated the prevalence of suicidal ideation and its relationship with depressive symptoms among Japanese workers.

Methods

For this purpose, a cross-sectional design was used. Major depressive disorder (MDD) and suicidal ideation in 1266 workers (1100 men and 166 women, aged 20–69 years) were assessed through clinical interviews conducted in accordance with the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders.

Results

A total of 34 and 70 participants were diagnosed with suicidal ideation and MDD, respectively. Suicidal ideation was especially prevalent in 40-year-olds to 49-year-olds. Six of the eight symptoms of MDD (depressive mood, loss of interest, weight loss, psychomotor agitation, worthlessness and concentration loss) were related to suicidal ideation. Depressive mood had the strongest relationship with suicidal ideation, followed by worthlessness and concentration loss. Worthlessness had the highest area under the curve in predicting suicidal ideation, followed by concentration loss and depressive mood.

Conclusions

We conclude that MDD symptoms—particularly depressive mood, worthlessness and concentration loss—are potential predictors of suicidal ideation in Japanese workers.
Famine in childhood and postmenopausal coronary artery calcification: a cohort study
Authors: Idris Nikmah S , Uiterwaal Cuno S P M , van der Schouw Yvonne T , van Abeelen Annet F M , Roseboom Tessa J , de Jong Pim A , Rutten Annemarieke , Grobbee Diederick E , Elias Sjoerd G
Published: November 2013

Objective

To assess the effects of famine exposure during childhood on coronary calcium deposition and, secondarily, on cardiac valve and aortic calcifications.

Design

Retrospective cohort.

Setting

Community.

Patients

286 postmenopausal women with individual measurements of famine exposure during childhood in the Netherlands during World War II.

Intervention/exposure

Famine exposure during childhood.

Main outcome measures

Coronary artery calcifications measured by CT scan and scored using the Agatston method; calcifications of the aorta and cardiac valves (mitral and/or aortic) measured semiquantitatively. Logistic regression was used for coronary Agatston score of >100 or ≤100, valve or aortic calcifications as the dependent variable and an indicator for famine exposure as the independent variable. These models were also used for confounder adjustment and stratification based on age groups of 0–9 and 10–17 years.

Results

In the overall analysis, no statistically significant association was found between severe famine exposure in childhood and a high coronary calcium score (OR 1.80, 95% CI 0.87 to 3.78). However, when looking at specific risk periods, severe famine exposure during adolescence was related to a higher risk for a high coronary calcium score than non-exposure to famine, both in crude (OR 3.47, 95% CI 1.00 to 12.07) and adjusted analyses (OR 4.62, 95% CI 1.16 to 18.43). No statistically significant association was found between childhood famine exposure and valve or aortic calcification (OR 1.66, 95% CI 0.69 to 4.10).

Conclusions

Famine exposure in childhood, especially during adolescence, seems to be associated with a higher risk of coronary artery calcification in late adulthood. However, the association between childhood famine exposure and cardiac valve/aortic calcification is less clear.
Fear of childbirth predicts postpartum depression: a population-based analysis of 511 422 singleton births in Finland
Authors: Räisänen Sari , Lehto Soili M , Nielsen Henriette Svarre , Gissler Mika , Kramer Michael R , Heinonen Seppo
Published: November 2013

Objectives

To study how reproductive risks and perinatal outcomes are associated with postpartum depression treated in specialised healthcare defined according to the International Classification of Diseases (ICD)-10 codes, separately among women with and without a history of depression.

Design

A retrospective population-based case–control study.

Setting

Data gathered from three national health registers for the years 2002−2010.

Participants

All singleton births (n=511 422) in Finland.

Primary outcome measures

Prevalence of postpartum depression and the risk factors associated with it.

Results

In total, 0.3% (1438 of 511 422) of women experienced postpartum depression, the prevalence being 0.1% (431 of 511 422) in women without and 5.3% (1007 of 18 888) in women with a history of depression. After adjustment for possible covariates, a history of depression was found to be the strongest risk factor for postpartum depression. Other strong predisposing factors for postpartum depression were fear of childbirth, caesarean birth, nulliparity and major congenital anomaly. Specifically, among the 30% of women with postpartum depression but without a history of depression, postpartum depression was shown to be associated with fear of childbirth (adjusted OR (aOR 2.71, 95% CI 1.98 to 3.71), caesarean birth (aOR 1.38, 95% CI 1.08 to 1.77), preterm birth (aOR 1.65, 95% CI 1.08 to 2.56) and major congenital anomaly (aOR 1.67, 95% CI 1.15 to 2.42), compared with women with no postpartum depression and no history of depression.

Conclusions

A history of depression was found to be the most important predisposing factor of postpartum depression. Women without previous episodes of depression were at an increased risk of postpartum depression if adverse events occurred during the course of pregnancy, especially if they showed physician-diagnosed fear of childbirth.
Baggage handler seniority and musculoskeletal symptoms: is heavy lifting in awkward positions associated with the risk of pain?
Authors: Bern Stine Hvid , Brauer Charlotte , Møller Karina Lauenborg , Koblauch Henrik , Thygesen Lau Caspar , Simonsen Erik Bruun , Alkjær Tine , Bonde Jens Peter , Mikkelsen Sigurd
Published: November 2013

Objectives

Heavy lifting is associated with musculoskeletal disorders but it is unclear whether it is related to acute reversible effects or to chronic effects from cumulated exposure. The aim of this study was to examine whether musculoskeletal symptoms in Danish airport baggage handlers were associated with their seniority as baggage handler, indicating chronic effects from cumulated workload.

Methods

We established a group of baggage handlers employed at Copenhagen Airport during the period 1983–2012 (n=3092) and a reference group of men in other unskilled occupations with less heavy work (n=2478). Data regarding work history, lifestyle and musculoskeletal symptoms were collected using a self-administered questionnaire (response rate 70.1% among baggage handlers and 68.8% among the reference group).

Results

The ORs of self-reported musculoskeletal symptoms during the last 12 months in the neck/upper back, lower back, shoulders, elbows, wrists, hips and knees were significantly higher in baggage handlers than in the reference group. These differences were explained by significant linear effects of baggage handler seniority for six anatomical regions. Adjustment for age, body mass index, smoking and leisure-time physical activity did not change these results. The findings were stable over age strata and among present and former baggage handlers.

Conclusions

The risk of musculoskeletal symptoms in six anatomical regions increased with increasing seniority as a baggage handler. This is consistent with the assumption that cumulated heavy lifting may cause chronic or long-lasting musculoskeletal symptoms. However, we cannot exclude that other factors related to baggage handler seniority may explain some of the associations.