bluuebunny/crossref_metadata_2025 huggingface dataset:
Inter‐sector water allocation in Israel, 2011–2050: urban consumption versus farm usage
Authors: Hadas Efrat , Gal Yoav
Published: November 2012

According to the Water Authority of Israel, Israel's water economy is on the brink of a crisis. Demands are increasing, exceeding the capacity of the natural sources, which are being depleted. Water, as a resource in short supply, necessitated administrative actions in order to attain its efficient utilization, in accordance with the goals set by the state. In addition, the issue of water allocation in Israel is strongly connected to internal politics and not necessarily to a clear overall policy. This article presents a simulation model which examined a large number of different scenarios and returns the possible outcomes of water allocations in a routine situation of uncertainty. The findings show that even under ideal conditions, a water shortage in Israel is inevitable and urban consumption will demand the largest allocation of water. As a result, the Israeli rural sector will be required to reorganize the water allocation system and production structure.
Knocking Suppression by Stratified Stoichiometric Mixture With Two-Zone Homogeneity in a DISI Engine
Authors: Bai Yun-long , Wang Jian-xin , Wang Zhi , Shuai Shi-jin
Published: November 2012

Knocking is the main obstacle of increasing the compression ratio in order to improve the thermal efficiency of gasoline engines. This paper proposes a concept of a stratified stoichiometric mixture (SSM) with two-zone homogeneity (TZH) for suppressing knocking and validated the concept by means of a numerical simulation and an experimental study in a DISI engine. The results show that the SSM can effectively suppress knocking and the knocking intensity decreases when the zone around the spark plug is richer and the end-gas zone is leaner. The less rich zone (fuel/air equivalent ratio of ϕ ≤ 1.2) of the SSM can speed up the initial burning velocity in order to avoid a thermal efficiency decrease, while the over rich zone (ϕ > 1.2) would decrease the combustion velocity when knocking was suppressed. The SSM leads to higher CO and lower HC and NOx emissions, which can be effectively after-treated using a three-way catalyst. The SSM can also reduce the decrease of power output compared to the method of retarding spark timing for suppressing knocking and has better fuel economy and fewer emissions than the method of enriching the mixture. The TZH can effectively alleviate combustion deterioration and soot formation due to the stratified mixture combustion. As a result, the SSM with TZH suppresses knocking, thus simultaneously lowering fuel consumption and emissions.
Mechanical Behavior of Internally Pressurized Copper Tube for New HVACR Applications
Authors: Kraft Frank F. , L. Jamison Tommy
Published: November 2012

This paper reviews and simplifies basic theory to predict plastic strain and burst pressure of internally pressurized, thin-walled copper tube for (heating, ventilation, air conditioning, and refrigeration applications. Predictions are based upon material stress–strain data obtained from basic tensile tests. A series of pressure tests was performed at 635 to 1500 psi (4.38–10.34 MPa), and until burst, on tubes ranging from 0.625 in. (15.87 mm) to 2.125 in. (53.97 mm) in diameter. A Voce type equation is shown to provide superior correlation to tensile and instability data, such that accurate projections can be made. An assessment of the classical power-law (Ludwik–Hollomon) equation is also presented, and it did not simultaneously correlate well with stress–strain data and satisfy the Considère instability criterion in uni-axial tension. Nevertheless, its use still led to reasonably accurate burst pressure predictions due to the strain range over which it was applied. Property variation (with respect to tube size) and anisotropy were observed in the transverse and axial tube directions for 1.125 in. (28.6 mm) and 2.125 in. (54.0 mm) diameter tube. Thus, the importance of representative and accurate material data in the transverse (hoop) direction is emphasized.
Weld Residual Stress in Various Large Diameter Nuclear Nozzles
Authors: Zhang Tao , Brust Frederick W. , Wilkowski Gery
Published: November 2012

Weld residual stresses in nuclear power plants can lead to cracking concerns caused by stress corrosion. Many factors can lead to the development of the weld residual stresses, and the distributions of the stress through the wall thickness can vary markedly depending on the weld processing parameters, nozzle and pipe geometries, among other factors. Hence, understanding the residual stress distribution is important in order to evaluate the reliability of pipe and nozzle welded joints. This paper represents an examination of the weld residual stress distributions which occur in different nozzles. The geometries considered here are large diameter thick wall pipe and nozzles. The detailed weld residual stress predictions for these nozzles are summarized. These results are categorized and organized in this paper and general trends for the causes of the distributions are established. The solutions are obtained using several different constitutive models including kinematic hardening, isotropic hardening, and mixed hardening model. Necessary fabrication procedures such as weld repair, overlay, and postweld heat treatment are also considered. The residual stress field can therefore be used to perform a crack growth and instability analysis. Some general discussions and comments are given in the paper.
Numerical and Experimental Investigation of the Aerodynamic Excitation of a Model Low-Pressure Steam Turbine Stage Operating Under Low Volume Flow
Authors: Megerle Benjamin , Stephen Rice Timothy , McBean Ivan , Ott Peter
Published: November 2012

The diversification of power generation methods within existing power networks has increased the requirement for operational flexibility of plants employing steam turbines. This has led to the situation where steam turbines may operate at very low volume flow conditions for extended periods of time. Under operating conditions where the volume flow through the last stage moving blades (LSMBs) of a low-pressure (LP) steam turbine falls below a certain limit, energy is returned to the working fluid rather than being extracted. This so-called “ventilation” phenomenon produces nonsynchronous aerodynamic excitation, which has the potential to lead to high dynamic blade loading. The aerodynamic excitation is often the result of a rotating phenomenon, with similarities to a rotating stall, which is well known in compressors. Detailed unsteady pressure measurements have been performed in a single stage model steam turbine operated with air under ventilation conditions. The analysis revealed that the rotating excitation mechanism observed in operating steam turbines is reproduced in the model turbine. A 3D computational fluid dynamics (CFD) method has been applied to simulate the unsteady flow in the air model turbine. The numerical model consists of the single stage modeled as a full annulus, along with the axial-radial diffuser. An unsteady CFD analysis has been performed with sufficient rotor revolutions to obtain globally periodic flow. The simulation reproduces the main characteristics of the phenomenon observed in the tests. The detailed insight into the dynamic flow field reveals information on the nature of the excitation mechanism. The calculations further indicate that the LSMB tip clearance flow has little or no effect on the characteristics of the mechanism for the case studied.
Modeling Spray Formation in Gas Turbines—A New Meshless Approach
Authors: Hoefler Corina , Braun Samuel , Koch Rainer , Bauer Hans-Joerg
Published: November 2012

A new meshless Lagrangian particle code has been developed to tackle the challenging numerical modeling of primary atomization. In doing so the correct treatment and representation of the interfacial physics are crucial prerequisites. Grid based codes using interface tracking or interface capturing techniques, such as the volume of fluid or level set method, exhibit difficulties regarding mass conservation, curvature capturing and interface diffusion. The objective of this work is to overcome these shortcomings of common state-of-the-art grid based approaches. Our multidimensional meshless particle code is based on the smoothed particle hydrodynamics (SPH) method. Various test cases have been conducted, by which the capability of accurately capturing the physics of single and multiphase flows is verified and the future potential of this approach is demonstrated. Compressible as well as incompresssible fluids can be modeled. Surface tension effects are taken into account by two different models. Solid walls as well as periodic boundary conditions offer a broad variety of numerically modeling technical applications. In a first step, single phase calculations of shear driven liquid flows have been carried out. Furthermore, the disintegration of a gravity driven liquid jet emerging from a generic nozzle has been investigated in free surface simulations. The typical formation of a meniscus due to surface tension is observed. Spray formation is qualitatively in good agreement compared to experiments. Finally, the results of a two-phase simulation with a fluid density ratio of 1000, which is similar to a fuel-air fluid system as in airblast atomizers, are presented. The surface minimization and pressure jump across the droplet interface due to surface tension can be predicted accurately. The test cases conducted so far demonstrate the accuracy of the existing code and underline the promising potential of this new method for successfully predicting primary atomization.
Nuclear Power in Europe 2012
Authors: Geraets Luc H. , Crommelynck Ir. Yves A.
Published: November 2012

Europe has been in the forefront of the development and implementation of the peaceful use of nuclear energy since the beginning, with the commissioning of the first nuclear plants in the world in the early fifties; today, nuclear power represents a significant contributor to the global energy supply in the continent (around 30%, i.e., almost twice as much as the world average). This paper investigates the current situation of nuclear in Europe, and whether there is a future for nuclear after the 2011 events. In preparation for the ASME PVP2013 conference to be held in Paris, France, next year, the paper aims at introducing our colleagues from all over the world into the European nuclear issues.
Transmission electron microscopy characterization of electrically stressed AlGaN/GaN high electron mobility transistor devices
Authors: Johnson Michael R. , Cullen David A. , Liu Lu , Sheng Kang Tsung , Ren Fan , Chang Chih-Yang , Pearton Stephen J. , Jang Soohwan , Johnson J. Wayne , Smith David J.
Published: November 2012

A set of AlGaN/GaN high electron mobility transistor devices has been investigated using step-stress testing, and representative samples of undegraded, source-side-degraded, and drain-side-degraded devices were examined using electron microscopy and microanalysis. An unstressed reference sample was also examined. All tested devices and their corresponding transmission electron microscopy samples originated from the same wafer and thus received nominally identical processing. Step-stressing was performed on each device and the corresponding current–voltage characteristics were generated. Degradation in electrical performance, specifically greatly increased gate leakage current, was shown to be correlated with the presence of crystal defects near the gate edges. However, the drain-side-degraded device showed a surface pit on the source side, and another region of the same device showed no evidence of damage. Moreover, significant metal diffusion into the barrier layer from the gate contacts was also observed, as well as thin amorphous oxide layers below the gate metal contacts, even in the unstressed sample. Overall, these observations emphasize that gate-edge defects provide only a partial explanation for device failure.
Comparison of neutron irradiation effects in AlGaN/AlN/GaN, AlGaN/GaN, and InAlN/GaN heterojunctions
Authors: Polyakov A. Y. , Smirnov N. B. , Govorkov A. V. , Kozhukhova E. A. , Pearton Stephen J. , Ren Fan , Liu Lu , Johnson J. W. , Lim Wantae , Kolin N. G. , Veryovkin S. S. , Ermakov V. S.
Published: November 2012

Neutron irradiation effects were compared for AlGaN/AlN/GaN high electron mobility transistor (HEMT) structures with Al composition in the AlGaN barrier ranging from 20% to 50%, “standard” Al0.25Ga0.75N/GaN HEMTs and for InAlN/GaN HEMTs with InAlN barrier lattice matched to GaN (17% In in the barrier). These samples were exposed to fast reactor neutrons with average energy ∼2 MeV and fluence of 1–3 × 1015 cm−2. The main effect of irradiation was the decrease of two-dimensional electron gas (2DEG) mobility and a positive shift in the threshold voltage corresponding to 2DEG depletion in capacitance–voltage characteristics. For the highest fluences, there was a decrease in both 2DEG concentration and accumulation capacitance, with the effect being strongest for AlGaN/AlN/GaN HEMTs with the highest Al composition and for InAlN/GaN HEMTs. The results correlate with the increase in concentration of deep negatively charged traps in the AlGaN or InAlN barrier with neutron dose. For applications in which tolerance to neutron irradiation is a concern, current high Al content AlGaN/AlN/GaN HEMTs and also InAlN/GaN structures are less radiation hard than low-Al-composition AlGaN/AlN/GaN and Al0.25Ga0.75N/GaN HEMTs.
Negative electron-beam resist hard mask ion beam etching process for the fabrication of nanoscale magnetic tunnel junctions
Authors: Chun Sung-Woo , Kim Daehong , Kwon Jihun , Kim Bongho , Lee Hyungyu , Lee Seung-Beck
Published: November 2012

The authors have demonstrated fabrication of 30 nm diameter perpendicular anisotropy magnetic tunnel junctions (MTJs) using negative electron-beam resist (NER) as the ion beam etching (IBE) hard mask. The NER pillar of 30 nm diameter and 105 nm thickness was fabricated by electron-beam lithography. The redeposition of the MTJ etching debris generated during the IBE on the outer surface of the NER pillar increased the lateral etch resistance of the resist polymer, allowing the edge profile to remain constant for the duration of the MTJ etching, resulting in a vertical MTJ sidewall profile. A multistep IBE (repetition of 45° primary etching and 30° secondary etching) was conducted to reduce the MTJ sidewall redeposition while reducing mechanical damage. The measurement results showed a tunnel magneto-resistance ratio of 22% at 30 nm junction diameter.
From sponge to dot arrays on (100) Ge by increasing the energy of ion impacts
Authors: Böttger Roman , Bischoff Lothar , Heinig Karl-Heinz , Pilz Wolfgang , Schmidt Bernd
Published: November 2012

Ge surfaces of up to 780 K temperature have been irradiated at normal incidence with up to 1017 Bi+ ions cm−2 having kinetic energies from 10 to 30 keV. The resulting surface morphologies have been studied by scanning electron microscopy. While at room temperature the impacts of high-energy Bi+ ions result in porous networks, at elevated irradiation temperatures hexagonally ordered dot arrays are formed, whereas after a further temperature increase the surface becomes smooth. The comprehensive experimental studies have been summarized in a phase diagram of surface morphologies in the ion energy versus substrate temperature plane. In this phase diagram, the onset of dot formation with increasing substrate temperature has been consistently modeled by nanomelting of the collision cascade volume of ion impacts, thereby taking into account the thermodynamic parameters of amorphous Ge (melt temperature, heat of fusion, and heat capacity) as well as the energy density deposited in the cascade volume as predicted by established simulation programs.
Fast simulation of stochastic exposure distribution in electron-beam lithography
Authors: Zhao Xinyu , Lee Soo-Young , Lee Sang-Hee , Kim Byung-Gook , Cho Han-Ku
Published: November 2012

The relative critical dimension variation of nanoscale features has become large enough to significantly affect the minimum feature size and maximum circuit density realizable in most lithographic processes. One source of such variation is the line edge roughness (LER). In the electron-beam lithographic process, the fluctuation of exposure (energy deposited) in the resist is one of the main factors contributing to the LER. It is essential to accurately estimate the exposure fluctuation for developing an effective method to reduce the LER. A possible method is to rely on the Monte Carlo simulation in computing the exposure distribution in a circuit pattern, i.e., generating a point spread function (PSF) for each point to be exposed, where the PSF is stochastic. While this approach can lead to a more realistic estimation, it is not practical due to its tremendous amount of computation required. In this paper, a new method to greatly reduce the number of PSF's to be generated without sacrificing the accuracy of estimating the exposure fluctuation is described. It generates only a small number of stochastic PSF's and uses them randomly in the exposure calculation for a circuit pattern. Through an extensive simulation, it is shown that the new method is statistically equivalent to generating a PSF for each point with an acceptable error. Since it is not necessary to know the exact spatial distribution of exposure for estimation of the LER, the new method has a good potential to be employed in practice to reduce the computation time by orders of magnitude.
Development of optical system with rotational misalignment adjustment for multi-optical-probe confocal microscopy
Authors: Lim Jiseok , Jung Myungki , Young Hwang Seo , Kang Shinill
Published: November 2012

Optical scanning confocal microscopy enables high-resolution imaging and optical sectioning for three-dimensional imaging. Technologies to improve confocal microscopy are being developed for applications, such as real-time bioinspection, fluorescence sample imaging, and ultra-high-resolution measurement. Recently, the need for high-resolution large-area inspection of electronics has been increasing rapidly, including large-area display panels. Therefore, the authors constructed an optical system for multi-optical-probe confocal microscopy. A 10 × 10 micro-objective-lens array was fabricated with high fidelity using an ultraviolet nanoimprinting process. To investigate the utility of this system, 1 × 1 mm2 images were examined using an XY-translation nanostage scanning with a travel length of 100 μm.
A Monte Carlo tool to study the mortality reduction due to breast screening programs
Authors: Zamora Luis I. , Forastero Cristina , Guirado Damián , Martínez‐Luna Rafael J. , Lallena Antonio M.
Published: November 2012

Purpose:

To develop a Monte Carlo tool that permits to study the reduction in breast cancer mortality rate due to breast screening programs.

Methods:

Simulations implement woman histories undergoing a screening program, include a model of survival after local treatment of invasive cancers and use distributions of time gained due to screening detection against symptomatic detection and overall sensitivity of the screening obtained previously. Mortalities for the whole woman population and for those women with ages within the range considered in the program have been calculated.

Results:

For the whole woman population, a reduction in breast cancer mortality up to 29% has been found for a configuration that includes women aged between 50 and 70 years, with a screening interval of two years and 100% acceptance rate. If an acceptance of 70% is considered, this percentage reduces to 20%. If, in the same conditions, the program starts at 40 years, the reduction of the mortality reaches 24% while if the screening interval is one year, this percentage raises to 28%. If mortalities are calculated for those women with ages within the range included in the program these reductions are greater and no significant differences are found between the programs with age ranges [50–70] and [40–70]. In the model, radio‐induced cancers have no effect in survival.

Conclusions:

The results agree reasonably well with those of different trials. Mortality reductions of 12%–20% (between two and four deaths per year and 105 women) are obtained only for acceptances above 50%. This could be considered as a threshold for the acceptance, which appears to be a critical parameter.
The second‐order differential phase contrast and its retrieval for imaging with x‐ray Talbot interferometry
Authors: Yang Yi , Tang Xiangyang
Published: November 2012

Purpose:

The x‐ray differential phase contrast imaging implemented with the Talbot interferometry has recently been reported to be capable of providing tomographic images corresponding to attenuation‐contrast, phase‐contrast, and dark‐field contrast, simultaneously, from a single set of projection data. The authors believe that, along with small‐angle x‐ray scattering, the second‐order phase derivativeΦ″s(x) plays a role in the generation of dark‐field contrast. In this paper, the authors derive the analytic formulae to characterize the contribution made by the second‐order phase derivative to the dark‐field contrast (namely, second‐order differential phase contrast) and validate them via computer simulation study. By proposing a practical retrieval method, the authors investigate the potential of second‐order differential phase contrast imaging for extensive applications.

Methods:

The theoretical derivation starts at assuming that the refractive index decrement of an object can be decomposed into δ = δs + δf, where δf corresponds to the objectˈs fine structures and manifests itself in the dark‐field contrast via small‐angle scattering. Based on the paraxial Fresnel‐Kirchhoff theory, the analytic formulae to characterize the contribution made by δs, which corresponds to the objectˈs smooth structures, to the dark‐field contrast are derived. Through computer simulation with specially designed numerical phantoms, an x‐ray differential phase contrast imaging system implemented with the Talbot interferometry is utilized to evaluate and validate the derived formulae. The same imaging system is also utilized to evaluate and verify the capability of the proposed method to retrieve the second‐order differential phase contrast for imaging, as well as its robustness over the dimension of detector cell and the number of steps in grating shifting.

Results:

Both analytic formulae and computer simulations show that, in addition to small‐angle scattering, the contrast generated by the second‐order derivative is magnified substantially by the ratio of detector cell dimension over grating period, which plays a significant role in dark‐field imaging implemented with the Talbot interferometry.

Conclusions:

The analytic formulae derived in this work to characterize the second‐order differential phase contrast in the dark‐field imaging implemented with the Talbot interferometry are of significance, which may initiate more activities in the research and development of x‐ray differential phase contrast imaging for extensive preclinical and eventually clinical applications.
Organization of the Influenza Virus Replication Machinery
Authors: Moeller Arne , Kirchdoerfer Robert N. , Potter Clinton S. , Carragher Bridget , Wilson Ian A.
Published: November 2012

Influenza Revealed

Influenza virus, a single-stranded RNA virus, is responsible for substantial morbidity and mortality worldwide. The influenza ribonucleoprotein (RNP) complex, which carries out viral replication and transcription, is central to the virus life-cycle and to viral host adaptation (see the Perspective by

Tao and Zheng

). Structural characterization of the viral RNP has been challenging, but

Moeller
et al.

(p.
1631
, published online 22 November) and

Arranz
et al.

(p.
1634
, published online 22 November) now report the structure and assembly of this complex, using cryo-electron microscopy and negative-stain electron microscopy. The structures reveal how the viral polymerase, RNA genome, and nucleoprotein interact in the RNP providing insight into mechanisms for influenza genome replication and transcription.
The Spatial and Temporal Origin of Chandelier Cells in Mouse Neocortex
Authors: Taniguchi Hiroki , Lu Jiangteng , Huang Z. Josh
Published: November 2012

Building Cross Connectivity

Chandelier cells innervate the initial segment of axons from pyramidal neurons and are thus placed to regulate pyramidal cell circuits in the brain. Chandelier cells of mice are marked by expression of the NKX2.1 transcription factor.

Taniguchi
et al.

(p.
70
, published online 22 November) followed the development of these neurons and found that chandelier cells originate from the ventral germinal zone. The nascent cells migrate and integrate with cortical neurons following specific developmental pathways.
Crystal Structure of the Calcium Release–Activated Calcium Channel Orai
Authors: Hou Xiaowei , Pedi Leanne , Diver Melinda M. , Long Stephen B.
Published: November 2012

Architecture of a CRAC

The calcium release–activated calcium (CRAC) channel generates intracellular calcium signals in response to depletion of calcium from the endoplasmic reticulum.

Hou
et al.

(p.
1308
, published online 22 November) report a high-resolution crystal structure of Orai, the CRAC channel pore from
Drosophila melanogaster.
Six Orai subunits surround a central pore that extends into the cytosol. The pore is in a closed conformation that is stabilized by anions binding to a basic region near the intracellular side. A ring of glutamates on the extracellular side form a selectivity filter. The channel architecture allows calcium permeation while regulating the flow to prevent overloading the cell with calcium.
Phase Transformations and Metallization of Magnesium Oxide at High Pressure and Temperature
Authors: McWilliams R. Stewart , Spaulding Dylan K. , Eggert Jon H. , Celliers Peter M. , Hicks Damien G. , Smith Raymond F. , Collins Gilbert W. , Jeanloz Raymond
Published: November 2012

Planetary Interiors Under Pressure

The interiors of Earth and other rocky planets generally consist of a few common minerals. Depending largely on the size of the planet, the distribution and relative abundance of these minerals varies; for example, MgO is abundant in the mantles of Earth and large Earth-like planets, but is present in Jupiter's core. The properties of MgO also vary with planetary size as a function of temperature and pressure.

McWilliams
et al.

(p.
1330
, published online 22 November) performed laser-shock experiments at pressures over three times higher than Earth's inner core. MgO underwent two phase transformations, first to a solid with a modified crystal structure, and then to a conductive liquid. In terrestrial planets greater than eight Earth masses, MgO in the mantle could generate a magnetic field–generating dynamo such as those that typically found in planetary cores.
Sport concussion knowledge base, clinical practises and needs for continuing medical education: a survey of family physicians and cross-border comparison
Authors: Lebrun Constance M , Mrazik Martin , Prasad Abhaya S , Tjarks B Joel , Dorman Jason C , Bergeron Michael F , Munce Thayne A , Valentine Verle D
Published: November 2012

Context

Evolving concussion diagnosis/management tools and guidelines make Knowledge Transfer and Exchange (KTE) to practitioners challenging.

Objective

Identify sports concussion knowledge base and practise patterns in two family physician populations; explore current/preferred methods of KTE.

Design

A cross-sectional study.

Setting

Family physicians in Alberta, Canada (CAN) and North/South Dakota, USA.

Participants

CAN physicians were recruited by mail: 2.5% response rate (80/3154); US physicians through a database: 20% response rate (109/545).

Intervention/instrument

Online survey.

Main and secondary outcome measures

Diagnosis/management strategies for concussions, and current/preferred KTE.

Results

Main reported aetiologies: sports/recreation (52.5% CAN); organised sports (76.5% US). Most physicians used clinical examination (93.8% CAN, 88.1% US); far fewer used the Sport Concussion Assessment Tool (SCAT1/SCAT2) and balance testing. More US physicians initially used concussion-grading scales (26.7% vs 8.8% CAN, p=0.002); computerised neurocognitive testing (19.8% vs 1.3% CAN; p<0.001) and Standardised Assessment of Concussion (SAC) (21.8% vs 7.5% CAN; p=0.008). Most prescribed physical rest (83.8% CAN, 75.5% US), while fewer recommended cognitive rest (47.5% CAN, 28.4% US; p=0.008). Return-to-play decisions were based primarily on clinical examination (89.1% US, 73.8% CAN; p=0.007); US physicians relied more on neurocognitive testing (29.7% vs 5.0% CAN; p<0.001) and recognised guidelines (63.4% vs 23.8% CAN; p<0.001). One-third of Canadian physicians received KTE from colleagues, websites and medical school training. Leading KTE preferences included Continuing Medical Education (CME) courses and online CME.

Conclusions

Existing published recommendations regarding diagnosis/management of concussion are not always translated into practise, particularly the recommendation for cognitive rest; predicating enhanced, innovative CME initiatives.
Have serological tests changed the face of childhood coeliac disease? A retrospective cohort study
Authors: Garnier-Lengliné Hélène , Brousse Nicole , Candon Sophie , Goulet Olivier , Ruemmele Frank M , Schmitz Jacques
Published: November 2012

Objectives

The aim of this study was to evaluate if the use of antitransglutaminase (tTG) and antiendomysium (EM) antibodies has modified the profile of coeliac disease (CD) in children.

Design

Retrospective cohort study.

Setting

Monocentric study, in one major tertiary centre in Paris. Two cohorts of patients were compared; the first included patients before the use of antibodies, and the second included patients after the use of antibodies.

Participants

All patients from the same physician diagnosed with a CD between 1976 and 1992 (historical cohort), and between 1994 and 2007, were included in the study. 56 patients were included in the historical cohort, 59 in the recent cohort.

Primary and secondary outcome measures

Clinical, biological and histological profiles at diagnosis have been studied.

Results

The recent cohort diagnosis of CD was based in 27% on a systematic screening (type I diabetes, n=10; CD in siblings, n=6). On comparison of CD patients in the historical to the recent cohort, the following significant differences were observed: Median age at diagnosis increased from 1 year to 2.7 years (p<0.0001). Patients in the historical cohort had more gastrointestinal symptoms (93% vs 63%, p=0.0001) and failure to thrive (98% vs 80%, p=0.0025). Nutritional deficiencies and morphological lesions were more severe in the historical cohort (90% subtotal or total villous atrophy vs 51%, p<0.0001). Differences observed between the two cohorts were mainly due to the presence of screened patients.

Conclusions

A new type of patients, with a paucisymptomatic or asymptomatic CD, has been identified using serological tests. Silent disease has been diagnosed by screening in a target population. In the other patients of the recent cohort, symptoms were similar but less severe than those observed before. Long-term risks of untreated silent CD are not well determined as yet, and have to be evaluated in prospective studies.
Validity of the SC-StepMX pedometer during treadmill walking and running
Authors: Colley Rachel C. , Barnes Joel D. , Leblanc Allana G. , Borghese Michael , Boyer Charles , Tremblay Mark S.
Published: November 2012

The purpose of this study was to examine the validity of the SC-StepMX pedometer for measuring step counts. A convenience sample of 40 participants wore 4 SC-StepMX pedometers, 2 Yamax DigiWalker pedometers, and 2 Actical accelerometers around their waist on a treadmill at 4 speeds based on each participant's self-paced walking speed (50%, 100%, 180%, and 250%; range: 1.4–14.1 km·h–1). The SC-StepMX demonstrated lower mean absolute percent error (–0.2%) compared with the Yamax DigiWalker (–20.5%) and the Actical (–26.1%). Mean measurement bias was lower for the SC-StepMX (0.1 ± 9.1; 95% confidence interval = –17.8 to 18.0 steps·min–1) when compared with both the Yamax DigiWalker (–15.9 ± 23.3; 95% confidence interval = –61.6 to 29.7 steps·min–1) and the Actical (–22.0 ± 36.3; 95% CI = –93.1 to 49.1 steps·min–1). This study demonstrates that the SC-StepMX pedometer is a valid tool for the measurement of step counts. The SC-StepMX accurately measures step counts at slower walking speeds when compared with 2 other commercially available activity monitors. This makes the SC-StepMX useful in measuring step counts in populations that are active at lower intensities (e.g., sedentary individuals, the elderly).
Diazotrophic bacteria reside inside Suillus tomentosus / Pinus contorta tuberculate ectomycorrhizae
Authors: Paul Leslie R. , Chapman William K. , Chanway Christopher P.
Published: November 2012

Culturable bacteria from Suillus tomentosus / Pinus contorta tuberculate ectomycorrhizae (TEM) tissues were evaluated to identify possible causative agents of TEM-associated nitrogenase activity in a naturally regenerating pine forest. Bacteria from internal and external TEM tissues were isolated over a 3 year sampling period and representative colony types were identified using gas chromatograph fatty acid methyl ester and 16S rDNA sequence analyses. Eighteen species of bacteria belonging to at least eight genera (Pseudomonas, Bacillus, Xanthomonas, Xanthobacter, Sphingobacterium, Burkholderia, Curtobacterium, and an actinomycete) were isolated from the TEM surface. In contrast, four bacterial species belonging to three genera (Paenibacillus, Methylobacterium, and Micrococcus) distinct from those found on the TEM surface were isolated from surface-sterilized TEM. None of the TEM surface isolates were diazotrophic but three of the four species from the TEM interior (Paenibacillus amylolyticus, Paenibacillus pabuli, and Methylobacterium mesophilicum) possessed the nifH gene and were capable of some acetylene reduction. Our findings indicate that nitrogen fixing bacteria also reside within TEM and should be considered as possible causative agents of TEM-associated nitrogenase activity on lodgepole pine.
Single-electron detachment cross sections of Co− and Ir− in collision with Ar and an empirical formula for single-electron detachment cross sections of negative ions in collision with Ar
Authors: Geng Zhixian , Bai Xue , Wei Baoren , Zhang Xuemei
Published: November 2012

The single-electron detachment (SED) cross sections for Co− and Ir− in collision with Ar in the energy region of 10–30 keV are obtained in our laboratory. As our previous paper reported, the SED cross sections have velocity and electron affinity dependency. Using the least-squares method, we analyze the available experimental data of SED cross sections for different negative ions in collision with Ar, and get empirical formulas for different sets of anionic projectiles. For most anionic projectiles, there is a clear correlation between increasing electron affinity and decreasing SED cross sections. Co and Ir, however, are an exception, and we discuss how other physical parameters can be taken into account in the search for general scaling rules for SED cross sections. As the incident velocity increases, the cross section dependence of the anion's electron affinity becomes weaker, and the relation between the SED cross sections and νp is supposed to be [Formula: see text].
Innovation and value creation in university–industry research centres in the Canadian forest products industry
Authors: Van Horne Constance , Poulin Diane , Frayret Jean-Marc
Published: November 2012

As the forest products industry evolves into a modern industry based on cutting-edge industrial and management research, the prevalence and importance of university research centres have gained importance. Although there has been increased funding and attention given to university–industry research centres from policy makers and researchers, little is still known about the benefits or value that these collaborations provide and create for firms. Applied academic research requires the active participation of researchers and practitioners. In the Canadian forest products industry, there are other important actors that need to be considered, the federal and provincial governments as owners and regulators of the resource and funders of research and development projects and intermediary organisations who are often charged with transforming academic results into tools and methods able to be implemented into industry firms. This paper presents the results of three comparative case studies of university–industry research centres operating in the Canadian forest products industry through an exploration of their knowledge and technology transfer processes. The goal is to better understand the value that has been created for the four main groups of actors involved though informal and formal transfer processes and which processes are best suited for different types of knowledge.
Post-thinning soil organic matter evolution and soil CO2 effluxes in temperate radiata pine plantations: impacts of moderate thinning regimes on the forest C cycle
Authors: Fernandez Irene , Álvarez-González Juan Gabriel , Carrasco Beatríz , Ruíz-González Ana Daría , Cabaneiro Ana
Published: November 2012

Forest ecosystems can act as C sinks, thus absorbing a high percentage of atmospheric CO2. Appropriate silvicultural regimes can therefore be applied as useful tools in climate change mitigation strategies. The present study analyzed the temporal changes in the effects of thinning on soil organic matter (SOM) dynamics and on soil CO2 emissions in radiata pine ( Pinus radiata D. Don) forests. Soil C effluxes were monitored over a period of 2 years in thinned and unthinned plots. In addition, soil samples from the plots were analyzed by solid-state 13C-NMR to determine the post-thinning SOM composition and fresh soil samples were incubated under laboratory conditions to determine their biodegradability. The results indicate that the potential soil C mineralization largely depends on the proportion of alkyl-C and N-alkyl-C functional groups in the SOM and on the microbial accessibility of the recalcitrant organic pool. Soil CO2 effluxes varied widely between seasons and increased exponentially with soil heating. Thinning led to decreased soil respiration and attenuation of the seasonal fluctuations. These effects were observed for up to 20 months after thinning, although they disappeared thereafter. Thus, moderate thinning caused enduring changes to the SOM composition and appeared to have temporary effects on the C storage capacity of forest soils, which is a critical aspect under the current climatic change scenario.
Fluoxetine inhibits monocrotaline-induced pulmonary arterial remodeling involved in inhibition of RhoA–Rho kinase and Akt signalling pathways in rats
Authors: Wang Han-Ming , Wang Yun , Liu Ming , Bai Yang , Zhang Xin-Hua , Sun Ying-Xian , Wang Huai-Liang
Published: November 2012

Activation of the small GTPase Ras homolog gene family member A (RhoA) and Rho-associated kinase (ROCK) are important in the pathogenesis of pulmonary arterial hypertension (PAH). Selective serotonin reuptake inhibitors inhibit activation of RhoA and ROCK in vitro, and ameliorate PAH and pulmonary arterial remodeling in vivo. However, little is known about whether the RhoA–ROCK signalling pathway is involved in the treatment of PAH with fluoxetine in vivo. The aim of the present study was to investigate the involvement of the RhoA–ROCK signalling pathway in the protective effect of the selective serotonin reuptake inhibitor fluoxetine against monocrotaline (MCT)-induced pulmonary arterial remodeling. MCT was applied to establish PAH in male Wistar rats. Fluoxetine was administered by gastric gavage once a day for 21 d. The results showed that MCT induced pulmonary arterial remodeling, raised the serotonylation and membrane translocation of RhoA in the lungs, and increased serotonin transporter (5-HTT), RhoA, and ROCK2 expression, and extracellular signal-regulated kinase (ERK) and Akt phosphorylation in the pulmonary arteries and the lungs. Fluoxetine markedly inhibited these MCT-induced changes. The findings suggest that fluoxetine inhibits MCT-induced pulmonary arterial remodeling in rats by inhibition of the RhoA–ROCK and Akt signalling pathways.
The influence of repeated administration of poloxamer 407 on serum lipoproteins and protease activity in mouse liver and heart
Authors: Korolenko Tatyana A. , Tuzikov Fedor V. , Johnston Thomas P. , Tuzikova Natalia A. , Kisarova Yana A. , Zhanaeva Svetlana Ya. , Alexeenko Tatyana V. , Zhukova Natalia A. , Brak Ivan V. , Spiridonov Victor K. , Filjushina Elena E. , Cherkanova Marina S. , Monoszon Anna A.
Published: November 2012

The effects of repeated administration of poloxamer 407 (P-407) on lipoprotein-cholesterol (LP-C) and lipoprotein-triglyceride (LP-TG) fractions and subfractions, as well as the effect on liver and heart proteases, were studied. Repeated administration of P-407 to male CBA mice resulted in a model of atherosclerosis with increased diastolic blood pressure; there was a drastic increase in total serum cholesterol and especially TG. A novel small-angle X-ray scattering method for the determination of the fractional and subfractional composition of LP-C and LP-TG was used. In chronically P-407-treated mice, P-407 significantly increased atherogenic low-density lipoprotein C (LDL-C) fractions, as well as intermediate-density lipoprotein C (IDL-C), and LDL1–3-C subfractions, and very-low-density lipoprotein-C (VLDL-C) fractions, as well as VLDL1–2-C and VLDL3–5-C subfractions), to a lesser extent, the total anti-atherogenic high-density lipoprotein C (HDL-C) fraction, as well as HDL2-C and HDL3-C subfractions. Additionally, we demonstrated an increase in the serum chitotriosidase activity, without significant changes in serum matrix metalloprotease (MMP) activity. Morphological changes observed in P-407-treated mice included atherosclerosis in the heart and storage syndrome in the liver macrophages. P-407 significantly increased the activity of cysteine, aspartate proteases, and MMPs in the heart, and only the activity of cathepsin B and MMPs in the liver of mice. Thus, repeated administration of P-407 to mice induced atherosclerosis secondary to sustained dyslipidemia and formation of foamy macrophages in liver, and also modulated the activity of heart and liver proteases.
Systemic and renal haemodynamic changes in renal schemia/reperfusion injury: impact of erythropoietin
Authors: Hussein Abdel-Aziz M. , Barakat Nashwa , Awadalla Amira , Shokeir Ahmed A.
Published: November 2012

The objective of this study was to investigate the effects of erythropoietin (EPO) on systemic and renal hemodynamics in a rat model of renal ischemic/reperfusion (I/R) injury. We used 30 male Sprague–Dawley rats distributed among the following 3 groups (10 rats per group): (i) the sham-operated group, (ii) the control group (I/R injury only), and (iii) the EPO-treated group (I/R injury with 1500 U EPO·(kg body mass)–1on day 0, and 500 U·kg–1on days 2 and 4 after ischemia). Renal function, arterial blood pressure (ABP), renal plasma flow (RPF), renal blood flow (RBF), and renal vascular resistance (RVR) were measured on days 1, 2, and 7 after ischemia. The expression of endothelial NO synthase (eNOS) and histopathology of kidney were evaluated on day 7. The contractility of aortic strips was recorded from the different groups. The results show that renal function and histopathology were significantly improved after treatment with EPO. Compared with the control group, the EPO-treated group showed a significant increase in RPF, RBF, haematocrite, ABP, eNOS expression, and a decrease in RVR (p < 0.05).The response of aortic strips to the relaxant effect of acetylcholine was improved in the EPO-treated group. In conclusion, treatment with EPO improves renal function and renal haemodynamics in renal I/R injury, and causes significant rise of ABP and haematocrite value.
Contraction-induced signaling: evidence of convergent cascades in the regulation of muscle fatty acid metabolism
Authors: Turcotte Lorraine P. , Abbott Marcia J.
Published: November 2012

The regulation of fatty acid utilization during muscle contraction and exercise remains to be fully elucidated. Evidence suggests that the metabolic responses of skeletal muscle induced by the contraction-induced changes in energy demand are mediated by the activation of a multitude of intracellular signaling cascades. This review addresses the roles played by 3 intracellular signaling cascades of interest in the regulation of fatty acid uptake and oxidation in contracting skeletal muscle; namely, the AMP-activated protein kinase (AMPK), calcium/calmodulin-dependent protein kinases (CaMKs), and the extracellular signal-regulated kinase 1 and 2 (ERK1/2) signaling cascades. Data delineating the potential role of AMPK in cross-talk with CaMKII, CaMK kinase (CaMKK), and ERK1/2 are presented. Collectively, data show that in perfused rodent muscle, regulation of fatty acid uptake and oxidation occurs via (i) CaMKII signaling via both AMPK-dependent and -independent cascades, (ii) CaMKK signaling via both AMPK-dependent and -independent cascades, (iii) AMPK signaling in a time- and intensity-dependent manner, and (iv) ERK1/2 signaling in an intensity-dependent manner.
The impact of doxorubicin and dexrazoxane injection of prepubertal female rats on pregnancy outcome and cardiac function postpartum
Authors: Calvé Annie , Noiles William , Sebag Igal A. , Chalifour Lorraine E.
Published: November 2012

Childhood cancer survivors can develop significant cardiac dysfunction in adulthood as a consequence of their cancer treatment. Studies have linked heart failure during pregnancy to childhood doxorubicin (DOX) exposure. We hypothesized that DOX injection would reduce cardiac function peripartum and that DOX-treated dams would show greater cardiac remodeling postweaning. Weanling female Sprague–Dawley rats were injected with phospate-buffered saline, DOX (3 mg/kg), or DOX plus the cardioprotectant dexrazoxane (DEX; 60 mg/kg) and followed for 2 pregnancies. DOX and DOX:DEX dams were fertile, but had fewer pups and more pup losses. Echocardiography, 1-day postpartum after each pregnancy, revealed greater increases in cardiac mass and eccentric hypertrophy in DOX-treated dams and early dilation in DOX:DEX dams. The expression of calcium homeostasis proteins can change after DOX treatment and cardiac remodeling. SERCA2a expression did not change. Reductions in phospholamban and phospho-serine 16-specific phospholamban expression in DOX dams were not relieved by DEX coinjection. DOX binds and inactivates calsequestrin 2 expression so increased calsequestrin 2 expression in DOX:DEX-treated dams suggests some DEX compensation. The eccentric hypertrophy and dilation development, despite compensatory changes in proteins controlling calcium cycling, suggest DOX damage with repeat pregnancy that was not alleviated fully by DEX.