bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative genetic parameters for wild stream‐living brown trout: heritability and parental effects
Authors: SERBEZOV D. , BERNATCHEZ L. , OLSEN E. M. , VØLLESTAD L. A.
Published: May 2010

Adaptability depends on the presence of additive genetic variance for important traits. Yet few estimates of additive genetic variance and heritability are available for wild populations, particularly so for fishes. Here, we estimate heritability of length‐at‐age for wild‐living brown trout (Salmo trutta), based on long‐term mark‐recapture data and pedigree reconstruction based on large‐scale genotyping at 15 microsatellite loci. We also tested for the presence of maternal and paternal effects using a Bayesian version of the Animal model. Heritability varied between 0.16 and 0.31, with reasonable narrow confidence bands, and the total phenotypic variance increased with age. When introducing dam as an additional random effect (accounting for c. 7% of total phenotypic variance), the level of additive genetic variance and heritability decreased (0.12–0.21). Parental size (both for sires and for dams) positively influenced length‐at‐age for juvenile trout – either through direct parental effects or through genotype‐environment correlations. Length‐at‐age is a complex trait reflecting the effects of a number of physiological, behavioural and ecological processes. Our data show that fitness‐related traits such as length‐at‐age can retain high levels of additive genetic variance even when total phenotypic variance is high.
Triamcinolone‐induced cataract in eyes with diabetic macular oedema: 3‐year prospective data from a randomized clinical trial
Authors: Gillies Mark C , Islam Fakir MA , Larsson Jörgen , Pasadhika Sirichai , Gaston Chris , Zhu Meidong , Wong Tien Y
Published: May 2010

Abstract

Purpose:  To describe the 3‐year risk of cataract after intravitreal triamcinolone (IVTA) injections for diabetic macular oedema and the outcomes of cataract surgery.

Methods:  Prospective data from a randomized clinical trial were analysed. At baseline, 27 phakic eyes with diabetic macular oedema were randomized to receive IVTA and 25 to receive sham injection. After 2 years, initial sham‐treated eyes were eligible to receive IVTA as the study became open label for the third year. The cumulative incidence of cataract surgery was the primary outcome of the study. Other outcomes assessed included progression of cataract, best‐corrected logarithm of the minimal angle of resolution visual acuity before and after surgery and central macular thickness.

Results:  Over the 3 years of the study, 15/27 (56%) phakic eyes in the IVTA treated group underwent cataract surgery as compared with 2/25 (8%) initial sham‐treated eyes (P < 0.001). Mean visual acuity 6 months after cataract surgery was better than at entry into the trial. Two (15%) of the eyes in the IVTA‐treated group undergoing cataract surgery had a loss of >15 letters. In the IVTA‐treated group, 10/15 (67%) eyes that had three or more injections had progression of posterior subcapsular cataract by ≥2 grades as compared with only 2/12 (17%) eyes that had fewer than three injections (P = 0.009).

Conclusions:  Over half of the eyes receiving IVTA injections for diabetic macular oedema required cataract surgery within 3 years. In eyes with three or more IVTA injections, two‐thirds had progression of posterior subcapsular cataract. Visual outcomes after cataract surgery were generally good, although a small proportion of eyes lost greater than 15 letters over the course of the study.
672. ARISTOLOCHIA BAETICA
Authors: Rix Martyn
Published: May 2010

Aristolochia baetica L. is illustrated, and its cultivation and pollination described. Its position within the genus in Europe and the Mediterranean region is discussed.
673. PASSIFLORA LINDENIANA
Authors: Vanderplank John , Rodriguez Carlos Magdalena
Published: May 2010

Passiflora lindeniana Triana & Planch. is described and illustrated. Its history, distribution, cultivation and conservation status are discussed.
674. PRIMULA NGHIALOENSIS
Authors: Rankin David W. H.
Published: May 2010

Primula nghialoensis D. W. H. Rankin, a new species from Vietnam is described. It is assigned to the section Chartacea (Balf. f.) W.W.Sm., and its relationships with other members of this section, particularly P. petelotii, are discussed.
Acute maternal social dysfunction, health perception and psychological distress after ultrasonographic detection of a fetal structural anomaly
Authors: Kaasen A , Helbig A , Malt UF , Næs T , Skari H , Haugen G
Published: May 2010

Please cite this paper as: Kaasen A, Helbig A, Malt U, Næs T, Skari H, Haugen G. Acute maternal social dysfunction, health perception and psychological distress after ultrasonographic detection of a fetal structural anomaly. BJOG 2010;117:1127–1138.

Objectives  To predict acute psychological distress in pregnant women following detection of a fetal structural anomaly by ultrasonography, and to relate these findings to a comparison group.

Design  A prospective, observational study.

Setting  Tertiary referral centre for fetal medicine.

Population  One hundred and eighty pregnant women with a fetal structural anomaly detected by ultrasound (study group) and 111 with normal ultrasound findings (comparison group) were included within a week following sonographic examination after gestational age 12 weeks (inclusion period: May 2006 to February 2009).

Methods  Social dysfunction and health perception were assessed by the corresponding subscales of the General Health Questionnaire (GHQ‐28). Psychological distress was assessed using the Impact of Events Scale (IES‐22), Edinburgh Postnatal Depression Scale (EPDS) and the anxiety and depression subscales of the GHQ‐28. Fetal anomalies were classified according to severity and diagnostic or prognostic ambiguity at the time of assessment.

Main outcome measures  Social dysfunction, health perception and psychological distress (intrusion, avoidance, arousal, anxiety, depression).

Results  The least severe anomalies with no diagnostic or prognostic ambiguity induced the lowest levels of IES intrusive distress (P = 0.025). Women included after 22 weeks of gestation (24%) reported significantly higher GHQ distress than women included earlier in pregnancy (P = 0.003). The study group had significantly higher levels of psychosocial distress than the comparison group on all psychometric endpoints.

Conclusions  Psychological distress was predicted by gestational age at the time of assessment, severity of the fetal anomaly, and ambiguity concerning diagnosis or prognosis.
NR2B‐NMDA receptor‐mediated increases in intracellular Ca2+concentration regulate the tyrosine phosphatase, STEP, and ERK MAP kinase signaling
Authors: Paul Surojit , Connor John A.
Published: May 2010

J. Neurochem.(2010)114, 1107–1118.

NMDA receptors regulate both the activation and inactivation of the extracellular signal‐regulated kinase (ERK) signaling cascade, a key pathway involved in neuronal plasticity and survival. This bi‐directional regulation of ERK activity by NMDA receptors has been attributed to opposing actions of NR2A‐ versus NR2B‐containing NMDA receptors, but how this is implemented is not understood. Here, we show that glutamate‐mediated intracellular Ca2+increases occur in two phases, a rapid initial increase followed by a delayed larger increase. Both phases of the Ca2+increase were blocked by MK‐801, a non‐selective NMDA receptor inhibitor. On the other hand, selective inhibition of NR2B‐NMDA receptors by Ifenprodil or Ro 25‐6981 blocked the delayed larger phase but had only a small effect on the rapid initial increase. The rapid initial increase in Ca2+, presumably because of NR2A‐NMDAR activation, was sufficient to activate ERK, whereas the large delayed increases in Ca2+mediated by NR2B‐NMDARs were necessary for dephosphorylation and subsequent activation of striatal‐enriched phosphatase, a neuron‐specific tyrosine phosphatase that in turn mediates the dephosphorylation and inactivation of ERK. We conclude that the magnitude of Ca2+increases mediated through NR2B‐NMDA receptors plays a critical role in the regulation of the serine/threonine and tyrosine kinases and phosphatases that are involved in the regulation of ERK activity.
White blood cell inactivation after treatment with riboflavin and ultraviolet light
Authors: Marschner Susanne , Fast Loren D. , Baldwin III William M. , Slichter Sherrill J. , Goodrich Raymond P.
Published: May 2010

Functional white blood cells (WBCs) in blood components may be responsible for a number of adverse transfusion effects, including transfusion‐associated graft‐versus‐host disease (TA‐GVHD), alloimmunization, and alloimmune platelet (PLT) refractoriness. TA‐GVHD occurs when functional lymphocytes are transfused into a patient who is unable to mount an immune response to the human leukocyte antigen (HLA) due to HLA compatibility or immunosuppression. Alloantibodies against HLA antigens on donor WBCs and PLTs are the major cause of refractoriness to PLT transfusions in patients receiving repeated blood transfusions. Attempts to reduce these undesirable effects have included leukoreduction filters and gamma irradiation. Studies have shown that exposure of PLT concentrates to riboflavin and light (Mirasol pathogen reduction technology [PRT], CaridianBCT Biotechnologies) causes irreparable modifications of nucleic acids that result in inactivation of a wide range of pathogens as well as inhibition of the immunologic responses mediated by WBCs present in PLT concentrates. This article summarizes these studies and also reports on additional findings from the Trial to Reduce Alloimmunization to Platelets (TRAP) and Mirasol Clinical Evaluation (MIRACLE) trials. Data from in vitro studies and this clinical trial suggest that PRT treatment may be as effective as gamma irradiation in preventing TA‐GVHD and more effective than leukoreduction in preventing alloimmunization.
Female donors and transfusion‐related acute lung injury
Authors: Middelburg Rutger A. , Van Stein Daniëlle , Zupanska Barbara , Uhrynowska Małgorzata , Gajic Ognjen , Muñiz‐Diaz Eduardo , Galvez Nuria Nogués , Silliman Christopher C. , Krusius Tom , Wallis Jonathan P. , Vandenbroucke Jan P. , Briët Ernest , Van Der Bom Johanna G.
Published: May 2010

BACKGROUND: Although quantitative evidence is lacking, it is generally believed that the majority of cases of transfusion‐related acute lung injury (TRALI) are caused by female blood donors. We aimed to examine the relation between female donors and the occurrence of TRALI.

STUDY DESIGN AND METHODS: We performed an international, multicenter case‐referent study. TRALI patients who were diagnosed clinically, independent of serology or donor sex, and had received transfusions either only from male donors or only from female donors (unisex cases) were selected. The observed sex distribution among the donors of these TRALI patients was compared to the expected sex distribution, based on the relevant donor populations.

RESULTS: Eighty‐three clinical TRALI cases were included; 67 cases received only red blood cells (RBCs), 13 only plasma‐rich products, and three both. Among RBC recipients the relative risk (RR) of TRALI after a transfusion from a female donor was 1.2 (95% confidence interval [CI], 0.69‐2.1) and among plasma‐rich product recipients the RR was 19 (95% CI, 1.9‐191). The p value for the difference between RBCs and plasma was 0.023.

CONCLUSION: Our data support the notion that plasma from female donors is associated with an increased risk of TRALI, while RBCs from female donors are not.
Safety of Implantable Pacemakers and Cardioverter Defibrillators in the Magnetic Field of a Novel Remote Magnetic Navigation System
Authors: JILEK CLEMENS , TZEIS STYLIANOS , REENTS TILKO , ESTNER HEIDI‐LUISE , FICHTNER STEPHANIE , AMMAR SONIA , WU JINJIN , HESSLING GABRIELE , DEISENHOFER ISABEL , KOLB CHRISTOF
Published: May 2010

Safety of Pacemakers and ICDs. Introduction: Electromagnetic interference with pacemaker and implantable cardioverter defibrillator (ICD) systems may cause temporary or permanent system malfunction of implanted devices. The aim of this study was to evaluate potential interference of a novel magnetic navigation system with implantable rhythm devices.

Methods: A total of 121 devices (77 pacemakers, 44 ICDs) were exposed to an activated NIOBE II® Magnetic Navigation System (Stereotaxis, St. Louis, MO, USA) at the maximal magnetic field strength of 0.1 Tesla and evaluated in vitro with respect to changes in parameter settings of the device, changes of the battery status/detection of elective replacement indication, or alterations of data stored in the device.

Results: A total of 115 out of 121 (95%) devices were free of changes in parameter settings, battery status, and internally stored data after repeated exposition to the electromagnetic field of the remote magnetic navigation system. Interference with the magnetic navigation field was observed in 6 pacemakers, resulting in reprogramming to a power‐on‐reset mode with or without detection of the elective replacement indication in 5 devices and abnormal variance of battery status in one device. All pacemakers could be reprogrammed to the initial modes and the battery status proved to be normal some minutes after the pacemakers had been removed from the magnetic field.

Conclusion: Interference of a remote magnetic navigation system (at maximal field strength) with pacemakers and ICDs not connected to leads with antitachycardic detection and therapies turned off is rare. Occurring functional abnormalities could be reprogrammed in our sample. An in vitro study will give information about interference of devices connected to leads. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1136‐1141)
Spark Plasma Sintering: An Easy Way to Make Infrared Transparent Glass–Ceramics
Authors: Delaizir Gaelle , Dollé Mickael , Rozier Patrick , Zhang Xianghua H.
Published: May 2010

Infrared transparent glass–ceramics have been prepared in the system GeS2–Sb2S3–CsCl using spark plasma sintering in shorter times in comparison with conventional thermal treatments. The combined effects of pressure, time, and temperature allow the controlled crystallization of Cs‐based crystals. The different glass–ceramics have been characterized by scanning electron microscopy and X‐ray diffraction. The optical properties were also investigated.
Ultraviolet Emission and Electrical Properties of Aluminum‐Doped Zinc Oxide Thin Films with Preferential C‐Axis Orientation
Authors: Zhang Daoli , Zhang Jianbing , Cheng Youguang , Yuan Lin , Miao Xiangshui
Published: May 2010

Aluminum‐doped zinc oxide (AZO) thin films with preferential c‐axis orientation were obtained on float glass substrates (25 mm × 76 mm × 1 mm) by sol–gel dip‐coating technique. Experimental results showed that annealing treatment influenced the c‐axis growth orientation of AZO thin films dramatically. Optical and electrical properties and microstructures of AZO thin films had been investigated systematically. The transmission spectra of the films demonstrated that the transmittance was higher than 90% in the visible region, and the four‐point probes technique measured the minimum resistivity of the films as 17.4 Ω·cm. Room‐temperature photoluminescence spectra indicated that AZO film had a broad emission peak at about 394 nm. Annealing treatment can enhance the ultraviolet emission of AZO thin films.
High Dielectric Constant and Low‐Loss Microwave Dielectric Ceramics Using (Zn0.95M2+0.05)Ta2O6(M2+=Mn, Mg, and Ni) Solid Solutions
Authors: Huang Cheng‐Liang , Chen Jhih‐Yong , Tseng Yu‐Wei , Jiang Chang‐Yang , Huang Guan‐Sian
Published: May 2010

High dielectric constant and low‐loss ceramics in the (Zn0.95M2+0.05)Ta2O6(M2+=Mn, Mg, and Ni) ceramic family have been prepared by the conventional mixed‐oxide route and their crystal structures and microwave dielectric properties have been investigated. The forming of (Zn0.95M2+0.05)Ta2O6(M2+=Mn, Mg, and Ni) solid solutions was confirmed by the X‐ray diffraction patterns, high‐resolution transmission electron microscopic lattice images, the energy‐dispersive X‐ray analysis, and the measured lattice parameters. The dielectric properties exhibited a significant dependence on the sintering condition and crystal structure of the ceramics. A fine combination of microwave dielectric properties can be achieved in the (Zn0.95Mn0.05)Ta2O6ceramics sintered at 1325°C for 2 h with a dielectric constant of ∼38.56, aQ×fvalue of ∼92 700 GHz (wheref=7.64 GHz, is the resonant frequency), and a temperature coefficient of resonant frequency (τf) of ∼8.9 ppm/°C. It is proposed as a suitable candidate material for small‐sized global positioning system patch antennas.
Spin‐Coating‐Derived Gold‐Nanoparticle Memory
Authors: Leu Ching‐Chich , Chen Shih‐Tang , Liu Fu‐Ken
Published: May 2010

A metal–oxide–semiconductor (MOS) capacitor embedded with gold nanoparticles (Au NPs) has been successfully fabricated by a spin‐coating‐derived chemical solution process. The colloidal synthesized Au NPs (∼3.5 nm) were self‐assembled to 3‐aminopropyltrimethoxysilane‐modified silicon oxide substrates. With the spin‐coating process, Au NPs can be fabricated onto silicon oxide with a high packing density of 1.6 × 1012 cm−2 in a short processing time. The sol–gel‐derived HfO2 layer, acting as a control oxide, was also spin coated to construct an Si/SiO2/Au NPs/HfO2 structure. This MOS structure showed good memory effect and retention properties. This study indicates that it is appropriate to utilize the spin‐coating process in nanocrystal memory applications.
Crystallization Behavior of SiO2–Al2O3–ZnO–CaO Glass System at 1123–1273 K
Authors: Chen Minghui , Zhu Shenglong , Wang Fuhui
Published: May 2010

The crystallization characteristics of a glass, used as the matrix of high‐temperature protective coatings, based on SiO2–Al2O3–ZnO–CaO with the addition of TiO2 and ZrO2 at a temperature range of 1123–1273 K have been investigated. At 1273 and 1173 K, tetragonal zirconia doped with Ti and Ca, initially precipitated from the melt. At 1123 K, however, zirconolite instead of zirconia precipitated as the primary phase. The secondary precipitates were zircon and titanite in the glass fired at 1273 K, titanite and willemite at 1173 K, and zirconolite, titanite, and willemite at 1123 K, respectively. It is proposed that the temperature‐dependent solubility of Ca and Ti in ZrO2 significantly affects the type and volume fraction of crystals precipitated from the glass.
Recombinant proteins in the diagnosis of toxoplasmosis
Authors: KOTRESHA DUPADAHALLI , NOORDIN RAHMAH
Published: May 2010

Kotresha D, Rahmah N. Recombinant proteins in the diagnosis of toxoplasmosis. APMIS 2010; 118: 529–42.

Toxoplasma gondii is an important human pathogen with a worldwide distribution. It is primarily of medical importance for pregnant women and immunocompromised patients. Primary infection of the former is often associated with fetal infection, which can lead to abortion or severe neonatal malformation. Immunocompromised patients are at risk of contracting the severe form of the disease that may be fatal. Thus, detection of T. gondii infection with high sensitivity and specificity is crucial in the management of the disease. Toxoplasmosis is generally diagnosed by demonstrating specific immunoglobulin M (IgM) and IgG antibodies to toxoplasma antigens in the patient’s serum sample. Most of the commercially available tests use T. gondii native antigens and display wide variations in test accuracy. Recombinant antigens have great potential as diagnostic reagents for use in assays to detect toxoplasmosis. Thus in this review, we address recent advances in the use of Toxoplasma recombinant proteins for serodiagnosis of toxoplasmosis.
Overweight and obesity trends in Copenhagen schoolchildren from 2002 to 2007
Authors: Pearson Seija , Hansen Bente , Sørensen Thorkild IA , Baker Jennifer L
Published: May 2010

Aim:  The purpose of this study is to monitor the prevalence trend in overweight and obesity among Copenhagen schoolchildren from the school years 2002 to 2007.

Methods:  Copenhagen community health service doctors conducted routine examinations at school entry (ages 5–8 years) and exit (ages 14–16 years). Body mass index (kg/m2) of 33 245 schoolchildren was calculated. The prevalence of overweight (including obesity) and obesity was classified using the International Obesity Task Force definitions.

Results:  From 2002 to 2007, although the prevalence of overweight (including obesity) in young girls decreased from 17.8 to 15.9%, the trend was non‐significant. In young boys, the trend slightly decreased, and the prevalence fell from 14.0 to 11.6%. In adolescent girls, the prevalence varied considerably and increased from 22.7 to 25.4% without a discernable trend. In adolescent boys, the trend slightly increased, and the prevalence rose from 15.8 to 18.9%. There were no significant changes in the prevalence of obesity.

Conclusion:  In contrast to the preceding decades, we identified a potential stagnation in the obesity epidemic among children but a continuing increase among adolescents. It remains critical to continue monitoring and to increase preventive measures to reduce the prevalence of overweight and obesity.
Development of Double Gear Fuel Pump for Heat Management Improvement
Authors: Matsunaga Yasushi , Morioka Noriko , Masuda Seiei , Kurosaki Masahiro
Published: May 2010

A unique double gear fuel pump system with operation mode switching capability for aircraft engines was developed to solve the heat management problem of current high efficiency turbofan engines and improve specific fuel consumption (SFC). Mode switching from parallel operations to series operations was found to reduce the discharge flow and pump work to nearly half. This resulted in the reduction of the rise in fuel temperature due to the fuel recirculation at the high altitude low Mach number flight condition. Air cooled oil cooler (ACOC) is usually required for sufficient oil cooling at descent or approach flight conditions. Since fuel consumption at those conditions is not very high, most of the gear pump discharge fuel flow proportional to the engine speed is returned to the fuel pump inlet resulting in significant heating. The ACOC that provides additional cooling capability degrades SFC due not only to the increased weight but also to the wasted fan discharge air. By reducing fuel temperature rise at the pump at those flight conditions, the necessity of ACOC may be eliminated. Further, it is shown that a reduction by half of the double gear pump weight can be achieved by increasing pump speed twice without incurring a durability penalty. Extensive tests showed sufficient steady state pump performance, switching characteristics, and durability.
Optical Transfer Function Measurements for Technically Premixed Flames
Authors: Schuermans Bruno , Guethe Felix , Mohr Wolfgang
Published: May 2010

This paper deals with a novel approach for measuring thermoacoustic transfer functions. These transfer functions are essential to predict the acoustic behavior of gas turbine combustion systems. Thermoacoustic prediction has become an essential step in the development process of low NOx combustion systems. The proposed method is particularly useful in harsh environments. It makes use of simultaneous measurement of the chemiluminescence of different species in order to obtain the heat release fluctuations via inverse method. Generally, the heat release fluctuation has two contributions: one due to equivalence ratio fluctuations, and the other due to modulations of mass flow of mixture entering the reaction zone. Because the chemiluminescence of one single species depends differently on the two contributions, it is not possible to quantitatively estimate the heat based on this information. Measurement of the transfer matrix based on a purely acoustic method provides quantitative results, independent of the nature of the interaction mechanism. However, this method is difficult to apply in industrial full-scale experiments. The method developed in this work uses the chemiluminescence time traces of several species. After calibration, an overdetermined inverse method is used to calculate the two heat release contributions from the time traces. The optical method proposed here has the advantage that it does not only provide quantitative heat release fluctuations but it also quantifies the underlying physical mechanisms that cause the heat release fluctuations: It shows what part of the heat release is caused by equivalence ratio fluctuations and what part by flame front dynamics. The method was tested on a full scale swirl-stabilized gas turbine burner. Comparison with a purely acoustic method validated the concept.
An Experimental Study of Swirling Supercritical Hydrocarbon Fuel Jets
Authors: Rachedi R. R. , Crook L. C. , Sojka P. E.
Published: May 2010

An experimental investigation was conducted to examine the behavior of swirling supercritical hydrocarbon fuel (SCF) jets injected into nitrogen environments whose temperatures and pressures exceeded the fuel critical values. Measurements of jet full-cone angle, mass concentration field, and penetration length were made using a schlieren system; the images were captured by a high-speed digital camera and processed using the camera’s software, plus MATLAB codes. Test parameters were the internal geometry of the pressure-swirl nozzle, fuel flow rate, and density ratio. The density ratio was varied by altering the reduced temperature of the injected fluid and nitrogen environment. SCF injections were studied at reduced temperatures (Tjet/Tcrit with both reported in Kelvin) ranging between 1.01 and 1.10, a reduced pressure (pjet/pcrit with both reported in bars) of 1.05, and fuel flowrates of 1.0 g/s, 2.0 g/s, and 3.0 g/s. The variable internal geometry pressure-swirl atomizer produced jets having swirl numbers (SN) of 0 (straight bore), 0.25, 0.50, and 1.00 (high swirl). As expected, increasing the swirl number for a SCF jet had by far the largest effect on jet cone angle, followed by a change in the density ratio; changing the fuel flow rate had very little effect. The SCF jet penetration length increased when either the fuel flow rate or density ratio increased. The mass concentration profiles demonstrated the jets to be self-similar in nature, and correlation to a Gaussian profile showed the mass concentration field to be independent of swirl number, density ratio, and fuel flow rate. Finally, it was found that there was a linear relationship between the jet half-width and the swirl number. The current study characterized the behavior of swirling hydrocarbon fuel SCF jets for the first time. Aspects of jet behavior similar to that of gas jets include: Gaussian mass concentration profiles and jet boundaries that scale with swirl number. Finally, CO2 was found to be a suitable surrogate fluid for hydrocarbon fuels since the behavior of the hydrocarbon SCF jets was similar to that of CO2 SCF jets.
A Modeling Approach to Predict Fretting Fatigue on Highly Loaded Blade Roots
Authors: Wackers Patrick , Arrieta Victor , Alquezar-Getan Marcel , Constantinescu Andrei , Maitournam Habibou
Published: May 2010

A lifing technique for predicting fretting fatigue on highly loaded blade-disk attachments has been developed and calibrated. The approach combines extensive testing on nickel and titanium based alloys using a specially devised multiaxial fretting test machine and an analytical lifing procedure, based on finite element contact calculations and multiaxial shakedown fatigue models. In order to reproduce realistic operational conditions and standardize testing conditions, a special fretting fatigue testing machine with high temperature testing capabilities was developed. The machine was employed to perform systematic testing under prescribed load and displacement conditions at representative temperatures. Making use of FEA, the rig test results were calculated to identify relevant parameters such as friction coefficient, slip conditions, and machine compliance. The computation procedure involves the calculation of several major loading cycles until a stabilized response of the structure is achieved. The material response is assumed to be elastoplastic, and a nonlinear friction law (space and time) was applied. From the computed mechanical variables, several life prediction models are benchmarked to establish their capabilities to predict fretting fatigue life. Finally, a most promising life estimation procedure was applied to predict life in a real compressor blade-disk attachment. Predicted failure location and number of cycles to failure are compared against engine test results. The experimental-analytical approach has the potential to predict fretting fatigue risk during the design phase on highly loaded joints, as well as estimating the preventive overhaul intervals for parts already in service.
Probabilistic Treatment of Crack Nucleation and Growth for Gas Turbine Engine Materials
Authors: Enright M. P. , McClung R. C. , Hudak S. J. , Francis W. L.
Published: May 2010

The empirical models commonly used for probabilistic life prediction do not provide adequate treatment of the physical parameters that characterize fatigue damage development. For these models, probabilistic treatment is limited to statistical analysis of strain-life regression fit parameters. In this paper, a model is proposed for life prediction that is based on separate nucleation and growth phases of total fatigue life. The model was calibrated using existing smooth specimen strain-life data, and it has been validated for other geometries. Crack nucleation scatter is estimated based on the variability associated with smooth specimen and fatigue crack growth data, including the influences of correlation among crack nucleation and growth phases. The influences of crack nucleation and growth variability on life and probability of fracture are illustrated for a representative gas turbine engine disk geometry.
HCCI Engine Combustion Phasing Prediction Using a Symbolic-Statistics Approach
Authors: Ghazimirsaied Ahmad , Shahbakhti Mahdi , Koch Charles Robert
Published: May 2010

Temporal dynamics of cyclic variation in a homogeneous charge compression ignition (HCCI) engine near misfire is analyzed using chaotic theory methods. The analysis of variation in consecutive cycles of CA50 (crank angle of 50% mass fraction fuel burnt) for an n-heptane fueled engine is performed for a test point near the misfire condition. The return map of the time series of CA50 cycle values reveals the deterministic and random portions of dynamics near misfire occurring in an HCCI engine. A symbol-statistic approach is also used to find the occurrence of possible probabilities of the data points under the same operating conditions. These techniques are then used to predict CA50 one cycle ahead. Simulated data points in phase space have similar dynamical structure to the experimental measurements.
Experimental and Numerical Studies on Nonlinear Dynamic Behavior of Rotor System Supported by Ball Bearings
Authors: Bai Changqing , Zhang Hongyan , Xu Qingyu
Published: May 2010

Ball bearings are important mechanical components in high-speed turbomachinery that is liable for severe vibration and noise due to the inherent nonlinearity of ball bearings. Using experiments and the numerical approach, the nonlinear dynamic behavior of a flexible rotor supported by ball bearings is investigated in this paper. An experimental ball bearing-rotor test rig is presented in order to investigate the nonlinear dynamic performance of the rotor systems, as the speed is beyond the first synchroresonance frequency. The finite element method and two-degree-of-freedom dynamic model of a ball bearing are employed for modeling the flexible rotor system. The discrete model of a shaft is built with the aid of the finite element technique, and the ball bearing model includes the nonlinear effects of the Hertzian contact force, bearing internal clearance, and so on. The nonlinear unbalance response is observed by experimental and numerical analysis. All of the predicted results are in good agreement with experimental data, thus validating the proposed model. Numerical and experimental results show that the resonance frequency is provoked when the speed is about twice the synchroresonance frequency, while the subharmonic resonance occurs due to the nonlinearity of ball bearings and causes severe vibration and strong noise. The results show that the effect of a ball bearing on the dynamic behavior is noticeable in optimum design and failure diagnosis of high-speed turbomachinery.
Contacting self-ordered molecular wires by nanostencil lithography
Authors: Gross L. , Schlittler R. R. , Meyer G. , Fendt L.-A. , Diederich F. , Glatzel Th. , Kawai S. , Koch S. , Meyer E.
Published: May 2010

The authors grew self-ordered meso-(4-cyanophenyl)-substituted Zn(II) porphyrin molecular wires on thin epitaxial NaCl(001) layers on top of the GaAs substrates under ultrahigh vacuum (UHV) conditions. Molecules assembled to one- and two-dimensional wires with a length of several 10 nm, depending on the substrate conditions. In addition, using the nanostencil tool, a shadow-masking technique in UHV, they evaporated Au and Cr electrodes having lateral dimensions in the 100 nm regime. The resulting combined molecular and metal structures were investigated in situ by means of noncontact atomic force microscopy (NC-AFM) and Kelvin probe force microscopy (KPFM). While NC-AFM enabled control of the tip-sample distance on the very complex and partly insulating surface, KPFM was used to determine and compensate changes in the local contact potential difference.
Potential dependent change in local structure of ferrocenyl-terminated molecular islands by electrochemical frequency modulation atomic force microscopy
Authors: Umeda Ken-ichi , Fukui Ken-ichi
Published: May 2010

Electroactive ferrocenylundecanethiol (FcC11H22SH) islands embedded in a n-heptanethiol (C7H15SH) self-assembled monolayer matrix on Au(111) were studied under potential control in 0.1M HClO4 aqueous solution using electrochemical frequency modulation atomic force microscopy. Signal of local structural change on the Fc islands upon oxidation from Fc0 to Fc+ was obtained in topography as a reversible process; however, the magnitude of the change was far less than expected in contrast to the case of the previous study for FcC11H22SH islands embedded in C10H21SH. Different degrees of freedom for the structures of the Fc islands originating from different molecular lengths for surrounding matrix molecules perhaps provide the distinct contrast between the two systems.
Theoretical simulation of noncontact atomic force microscopy in liquids
Authors: Tsukada M. , Watanabe N. , Harada M. , Tagami K.
Published: May 2010

Methods of theoretical simulations of noncontact atomic force microscopy in liquids have been developed. Though there are several difficult issues for the theoretical simulations in liquids, the authors introduce here the simulation methods for the cantilever oscillation in liquids and the tip-sample interaction force mediated by water molecules. As for the cantilever motion, a very efficient numerical method is proposed which solves the oscillation of the elastic beam cantilever and fluid dynamics simultaneously. The results reproduce fairly well the resonant curve and related properties of the Si beam cantilever. As for the simulation of the tip-sample interaction force in water, classical molecular dynamics (MD) method is adopted in the present work. The case study by MD for the mica surface in water revealed new features that appeared in the three-dimensional force map.
Fabrication of regular arrays of gold nanospheres by thermal transformation of electroless-plated films
Authors: Ahn Wonmi , Blake Phillip , Shultz John , Ware Morgan E. , Roper D. Keith
Published: May 2010

Rectangular lattices of gold nanospheres have been fabricated by thermally annealing Au nanopillars and nanocylinders deposited via electroless plating onto indium-tin-oxide glass substrates in a novel method. The substrates were patterned using e-beam lithography, and particle size and shape were controlled by adjusting the thickness of the poly(methylmethacrylate) mask, e-beam power, and electroless plating parameters. Nanostructures produced by this electroless plating method exhibited greater coalescence than sputtered gold films. Attachment of electroless-plated structures to indium-tin-oxide substrates was stable to stringent thermal, solvent, and electromagnetic exposures. This facile and versatile method is applicable to the fabrication of regular metal nanoparticle array platforms for improved optical and plasmonic features in sensing and imaging devices.
Development of ion sources from ionic liquids for microfabrication
Authors: Perez-Martinez Carla , Guilet Stéphane , Gogneau Noëlle , Jegou Pascale , Gierak Jacques , Lozano Paulo
Published: May 2010

In this article the authors present the potential of ionic liquid ion sources (ILISs) for direct microfabrication of silicon structures. The authors have developed a specific source geometry using the ionic liquid EMI-BF4 to obtain stable emission currents up to the 10 μA regime. ILIS (EMI-BF4) engraving properties were then investigated. The results and the chemical analysis of the patterned substrates suggest that reactive ion species can be generated from ILIS. This possibility is of major interest to allow decisive advances in the field of focused ion beam applications.
Stochastic Community Assembly Causes Higher Biodiversity in More Productive Environments
Authors: Chase Jonathan M.
Published: May 2010

Biodiversity and Productivity

When data are analyzed at relatively large spatial scales, biodiversity generally increases with productivity, but the pattern at smaller scales is more variable.
Chase
(p.
1388
, published online 27 May) presents results from a 7-year experiment in artificial ponds. β-diversity (the variation in species composition from site to site) in animal species was persistently higher at higher productivity among otherwise homogeneous environments in this controlled experimental venue. This pattern appeared to result from shifts in the relative importance of deterministic versus stochastic community assembly mechanisms along the productivity gradient. Thus, variation in the mechanism of community assembly might be an important process determining the relationship between biodiversity and productivity.
c-di-AMP Secreted by Intracellular
Listeria monocytogenes
Activates a Host Type I Interferon Response
Authors: Woodward Joshua J. , Iavarone Anthony T. , Portnoy Daniel A.
Published: May 2010

Bacterial (Interferon)ce

Intracellular bacterial pathogens, such as
Listeria monocytogenes
, are detected in the cytosol of host immune cells, where they induce a host response that is often dependent on microbial secretion systems.

Woodward
et al.

(p.
1703
, published online 27 May) now show that
L. monocytogenes
produce and release cyclic diadenosine monophosphate into the host cytosol, which induces the production of host type I interferon. Because a number of intracellular pathogens contain the protein machinery to generate this nucleotide and also activate this same innate immune pathway, a common molecular mechanism may exist for host detection of cytosolic bacterial pathogens.
Late-glacial (Allerød – Younger Dryas) Coleoptera from central Cape Breton Island, Nova Scotia, Canada
Authors: Miller Randall F.
Published: May 2010

Coleoptera from three late-glacial sites on Cape Breton Island, Nova Scotia, Canada, provide proxy climate data from 12 600 to 10 400 BP. Samples older than about 11 800 BP contain tundra to tree-line species. Between 11 800 and about 10 800 BP, beetle assemblages become typical of the modern boreal forest. Beetles younger than 10 800 BP responded to climatic deterioration during the Younger Dryas. Although coleopteran evidence for the Younger Dryas is not as strong as that presented by palynological and stratigraphic studies, the appearance of Olophrum boreale and other species found today in the northern boreal forest and on tundra or coastal tundra corresponds with the decline of shrub birch and the rise in willow and alder pollen. Beetles responded just as likely to changes in vegetation and ground cover as to changes in temperature. The extent to which Coleoptera were affected may lie somewhere between a moderated continental response seen in the Great Lakes region in North America and more extreme changes recorded in Europe. This response is consistent with shifts in the North Atlantic oceanic Polar Front in the Ruddiman and McIntyre model.
Two billion year old isotopically heavy carbon: evidence from the Labrador Trough, Canada
Authors: Melezhik V. A. , Fallick A. E. , Clark T.
Published: May 2010

Forty-eight samples of bulk carbonates were studied from the Dunphy, Portage, Alder, Uvé, Denault, and Abner formations and the undivided Pistolet subgroup in the Labrador Trough, Quebec, Canada. The carbonate units occur as a number of thick beds (up to 300 m) within 100–600 m thick formations. They are interbedded with siliciclastic sediments and are composed of crystalline, sparry, micritic allochemical and stromatolitic dolostones. The carbonate rocks are recrystallized and metamorphosed (up to amphibolite grade). They are chemically dolostones, and include chemical or biochemical laminated and massive dolostones, dolorudites, dolarenites, and dololitites, which were deposited in shallow-water (Dunphy, Denault, and Abner formations) to relatively deep water (Uvé Formation) marine environments. Reef facies are present in the Denault and Abner formations. The Dunphy, Portage, Alder, and Uvé formations, deposited between 2.17 and 2.14 Ga, yield isotopically heavy values of δ13C(PDB) ranging from + 5.3 to + 15.4‰, whereas δ18O(SMOW) values range from + 16.2 to + 25.4‰, which is rather normal for Precambrian sedimentary carbonates. The average values of δ13C show a decreasing trend upwards in the stratigraphy from 14.8 ± 0.5‰ (Dunphy Formation), to 9.5 ± 0.7‰ (Alder Formation), to 8.0 ± 1.7‰ (Uvé Formation). Average δ18O values exhibit a similar tendency, 23.6 ± 1.1, 22.6 ± 1.1, and 20.0 ± 1.9‰, respectively. The Alder and Uvé formations display clustering in a δ13C histogram, while the Dunphy Formation plots as a separate offset. The Abner and Denault formations, deposited at about 1.88 Ga, show an average δ13C of 2.1 ± 0.6 and 1.3 ± 1.4‰, and an average δ18O of 21.4 ± 1.9 and 22.6 ± 2.0‰, respectively. δ13C for these two formations is similar to that of Recent marine carbonates. The isotopically heavy carbonates (13Ccarb) of the Dunphy, Portage, Alder, and Uvé formations and those of the undivided Pistolet subgroup were accumulated during approximately 30 Ma over a vast area of at least 20 000 km2. The 13Ccarb enrichment occurs in connection with diverse depositional environments, not controlled by any detectable local factors (e.g., facies, diagenetic or metamorphic alteration) and therefore considered to be part of the world-wide development of high δ13Ccarb documented at around 2.2 ± 0.1 Ga. The Canadian Shield is the fourth continent, in addition to Africa, northern Europe, and Australia, to show extensive development of isotopically heavy carbonate formations of this age.
Nd-isotope evolution of Archaean plutonic rocks in southeastern Superior Province
Authors: Bédard L. Paul , Ludden John N.
Published: May 2010

The Opatica plutonic belt, Abitibi greenstone belt, and Pontiac Subprovince represent a major proportion of the southeastern Superior Province, which was formed and accreted rapidly between approximately 2.9 and 2.8 Ga. Plutons in these belts are grouped into four types: (i) trondhjemite–tonalite–granodiorite (TTG) suite (2.82–2.69 Ga), (ii) monzodiorite (MZD) suite (2.697–2.669 Ga), (iii) late alkaline granitoid (ALK) suite (2.68–2.67 Ga), and (iv) anatectic granite and monzonite (ANA) suite (2.69–2.64 Ga). The four suites are represented in all belts and show similar petrography and geochemistry. In terms of Nd-isotope composition, the TTG, MZD, and ALK suites are typical of destructive plate margin magmatism and have + 1.4 < initial εNd < +3.7, values which are very similar to that of the Abitibi mantle (εNd + 2.5). The lower values for the ANA suites (εNd + 0.1 to + 2.4) result from recycling of crustal components. In the Opatica belt the ANA granitoids fall on the Nd-isotope evolution curve defined by the Opatica TTG plutons, and are thus considered to be melt products of this suite. However, Abitibi and Pontiac ANA suites show a larger range of εNd, from + 0.1 to + 2.4, compared with + 1.0 to + 1.3 for the Opatica, suggesting more heterogeneous crustal source rock. Recent geological mapping and geophysical studies associated with the Lithoprobe project have suggested that the Opatica belt represents a plutonic belt against which the Abitibi was accreted by subduction-related collision and that the Pontiac Subprovince is dominated by imbricated metasediments related to the final stages of collision in the Abitibi region. The Nd-isotope data provide support for these arguments. Early plutonic suites are mantle derived and related to arc-accretion processes. As the collision process progresses, a more evolved isotopic component is introduced, possibly in relation to sediment subduction into the mantle. Anatexis of the crust in the central Opatica belt and the core of the Pontiac Subprovince resulted in the formation of granites with a crustal signature for Nd isotopes.
Structure and kinematics of a major tectonic contact, Michipicoten greenstone belt, Ontario
Authors: McGill George E.
Published: May 2010

The Michipicoten greenstone belt, Ontario, experienced a complex history of folding, faulting, and fabric development. Near Wawa, a major east–west contact, here named the Steep Hill Falls (SHF) contact, extends entirely across the belt. The SHF contact is both an angular unconformity and a fault and is interpreted to be a regionally significant tectonic contact separating distinct northern and southern terranes, both of which include volcanic rocks of probable island-arc origin. The amount of horizontal transport involved in bringing the two terranes together along the SHF contact is not known. Mapping and structural analysis suggest that regionally significant horizontal displacements took place, with movement vectors that changed with time. Early faults, folds, and fabrics imply north–south to northeast–southwest (with respect to present directions) convergence, with a vergence reversal occurring during this complex event. The most likely models infer early south vergence and later north vergence. Transecting the earliest structures are younger (but still Archean) northeast-striking steep cleavages with associated upright folds that may relate to northwest–southeast assembly of the Superior Province craton. The craton assembly event thus involved a transport direction at a high angle to that inferred for the earlier assembly of the Michipicoten greenstone belt.