bluuebunny/crossref_metadata_2025 huggingface dataset:
Truncation correction for oblique filtering lines
Authors: Hoppe Stefan , Hornegger Joachim , Lauritsch Günter , Dennerlein Frank , Noo Frédéric
Published: December 2008

State‐of‐the‐art filtered backprojection (FBP) algorithms often define the filtering operation to be performed along oblique filtering lines in the detector. A limited scan field of view leads to the truncation of those filtering lines, which causes artifacts in the final reconstructed volume. In contrast to the case where filtering is performed solely along the detector rows, no methods are available for the case of oblique filtering lines. In this work, the authors present two novel truncation correction methods which effectively handle data truncation in this case. Method 1 (basic approach) handles data truncation in two successive preprocessing steps by applying a hybrid data extrapolation method, which is a combination of a water cylinder extrapolation and a Gaussian extrapolation. It is independent of any specific reconstruction algorithm. Method 2 (kink approach) uses similar concepts for data extrapolation as the basic approach but needs to be integrated into the reconstruction algorithm. Experiments are presented from simulated data of the FORBILD head phantom, acquired along a partial‐circle‐plus‐arc trajectory. The theoretically exact M‐line algorithm is used for reconstruction. Although the discussion is focused on theoretically exact algorithms, the proposed truncation correction methods can be applied to any FBP algorithm that exposes oblique filtering lines.
Clinical application of radiophotoluminescent glass dosimeter for dose verification of prostate HDR procedure
Authors: Hsu Shih‐Ming , Yeh Chien‐Yi , Yeh Tien‐Chi , Hong Ji‐Hong , Tipton Annie Y. H. , Chen Wei‐Li , Sun Shung‐Shung , Huang David Y. C.
Published: December 2008

High dose rate brachytherapy (HDR‐BT) is one of the many modalities for prostate cancer treatment. Due to the nature of HDR‐BT, in vivo dosimetry is feasible and can be used to verify consistent dose delivery. In order to validate a dose verification system for HDR‐BT prostate cancer treatment, a radiophotoluminescent glass dosimeter (RPLGD) was used and the measurements were compared with those from a thermoluminescent dosimeter. The RPLGD shows many advantages in HDR‐BT dose measurement, such as repeatability, stability, and small effective size. These advantages make the RPLGD a superior option for use as a dosimeter in HDR‐BT. The results described here show that the difference between the measured dose and the treatment planned dose is less than 5%. A Monte Carlo simulation for the dose was performed using Monte Carlo ‐particle to investigate position error. This study concludes that the RPLGD is a promising and reliable dosimeter for HDR‐BT in vivo dosimetry with clinically acceptable accuracy.
Implications of resolution and noise for in vivo micro‐MRI of trabecular bone
Authors: Li Charles Q. , Magland Jeremy F. , Rajapakse Chamith S. , Guo X. Edward , Zhang X. Henry , Vasilic Branimir , Wehrli Felix W.
Published: December 2008

Osteoporotic bone loss is accompanied by impaired structural integrity of the trabecular network, leading to a decrease in the overall mechanical properties of the bone. The development of the “virtual bone biopsy” (VBB), a method combining magnetic resonance microimaging and digital image processing techniques, has previously been shown to quantify topology and scale of human trabecular bone noninvasively. The aim of this work was to determine the extent to which structural parameters derived from images acquired in the limited spatial resolution regime of in vivo imaging are sensitive to resolution and noise and further, whether under these conditions, a small amount of bone loss and its associated structural manifestations can be detected. Toward these goals 3D models of trabecular bone representing multiple anatomic locations were generated on the basis of images of human cadaveric bone cores. These images were binarized and the resulting data arrays representing pure bone (proton ) and pure marrow () subjected to simulated MR imaging by Cartesian sampling of space, yielding, after 3D Fourier reconstruction, voxel sizes currently achievable in vivo. Subsequently, realistic levels of Gaussian noise were superimposed on the complex data and magnitude images were computed. The resulting images were subsequently VBB processed for a range of signal‐to‐noise ratio (SNR) values and image voxel sizes. For comparison of the predicted behavior to in vivo data, images from a recent patient study were evaluated as well. Systematic changes of the derived structural parameters changing progressively with decreasing SNR were noted, and it is shown that the errors are correctable using simple linear transformations, thereby allowing the data to be normalized. The predicted dependence of the structural parameters on SNR also closely parallel those observed in vivo. Finally, in order to assess the sensitivity of the VBB processing algorithms to detect bone loss during disease progression or regression in response to treatment, the high‐resolution specimen data were subjected to 5% bone loss either by homogeneous or heterogeneous erosion and images simulated at in vivo resolution and SNR. At typical in vivo SNR and effective image resolution ( isotropic and ), VBB algorithms were able to detect the structural implications of a 5% loss in bone volume fraction with high statistical significance.
The optimal optical readout for the x‐ray light valve—Document scanners
Authors: Oakham P. , MacDougall Robert D. , Rowlands J. A.
Published: December 2008

The x‐ray light valve (XLV) is a novel, potentially low‐cost, x‐ray detector that converts an x‐ray exposure into an optical image stored in a liquid crystal cell. This optical image is then transferred from the liquid crystal cell to a computer through an optical‐to‐digital imaging readout system. Previously, CCD‐based cameras were used for the optical readout, but recently it was proposed that an inexpensive optical scanner, such as an office document scanner, is a better match to the optical properties of the XLV. A methodology for characterizing a document scanner's ability to produce medical quality images from the XLV is outlined and tested on a particular scanner (Canon LiDE 30). This scanner was shown to have key characteristics of a medical device—a linear response, dynamic range sufficient for chest radiography (although not mammography) in a single pass, and an MTF and NPS that exceed the requirements for all medical applications of the scanner. This combination of criteria shows that a document scanner can be used as a digitization method for the XLV.
Medical Effects of Ionizing Radiation: 3rd Edition
Authors: Hendee William
Published: December 2008

Medical Effects of Ionizing Radiation: 3rd Edition Mettler F. A. and Upton A. C. Saunders/Elsevier Publishers, Philadelphia, 2008. 564 pp. Price: $198.20 (hardcover) ISBN 978‐0‐7216‐0200‐4.
A Stress Signaling Pathway in Adipose Tissue Regulates Hepatic Insulin Resistance
Authors: Sabio Guadalupe , Das Madhumita , Mora Alfonso , Zhang Zhiyou , Jun John Y. , Ko Hwi Jin , Barrett Tamera , Kim Jason K. , Davis Roger J.
Published: December 2008

A high-fat diet causes activation of the regulatory protein c-Jun NH
2
-terminal kinase 1 (JNK1) and triggers development of insulin resistance. JNK1 is therefore a potential target for therapeutic treatment of metabolic syndrome. We explored the mechanism of JNK1 signaling by engineering mice in which the
Jnk1
gene was ablated selectively in adipose tissue. JNK1 deficiency in adipose tissue suppressed high-fat diet–induced insulin resistance in the liver. JNK1-dependent secretion of the inflammatory cytokine interleukin-6 by adipose tissue caused increased expression of liver SOCS3, a protein that induces hepatic insulin resistance. Thus, JNK1 activation in adipose tissue can cause insulin resistance in the liver.
Activation of Pannexin-1 Hemichannels Augments Aberrant Bursting in the Hippocampus
Authors: Thompson Roger J. , Jackson Michael F. , Olah Michelle E. , Rungta Ravi L. , Hines Dustin J. , Beazely Michael A. , MacDonald John F. , MacVicar Brian A.
Published: December 2008

Pannexin-1 (Px1) is expressed at postsynaptic sites in pyramidal neurons, suggesting that these hemichannels contribute to dendritic signals associated with synaptic function. We found that, in pyramidal neurons,
N
-methyl-
d
-aspartate receptor (NMDAR) activation induced a secondary prolonged current and dye flux that were blocked with a specific inhibitory peptide against Px1 hemichannels; knockdown of Px1 by RNA interference blocked the current in cultured neurons. Enhancing endogenous NMDAR activation in brain slices by removing external magnesium ions (Mg
2+
) triggered epileptiform activity, which had decreased spike amplitude and prolonged interburst interval during application of the Px1 hemichannel blocking peptide. We conclude that Px1 hemichannel opening is triggered by NMDAR stimulation and can contribute to epileptiform seizure activity.
Use of the Novel INNO-LiPA Line Probe Assay for Detection of Hepatitis B Virus Variants That Confer Resistance to Entecavir Therapy
Authors: Jardi Rosendo , Rodriguez-Frias Francisco , Tabernero David , Homs Maria , Schaper Melanie , Esteban Rafael , Buti Maria
Published: December 2008

A line probe assay (INNO-LiPA DR, version 3) for the detection of hepatitis B virus mutations that confer resistance to entecavir therapy was evaluated. The INNO-LiPA DR assay is a highly sensitive assay that is easily applicable for the detection and monitoring of entecavir resistance-conferring mutations and is more sensitive than sequencing for the detection of mixed sequences.
Using electronic/computer interventions to promote physical activity: Table 1
Authors: Marcus B H , Ciccolo J T , Sciamanna C N
Published: December 2008

The internet has been used as a method to deliver various health interventions (eg, weight management, smoking cessation, increasing physical activity). An electronic search (ie, PubMed, PsycInfo, Web of Science) for internet-based physical activity interventions among adults yields fewer than 25 studies. Although many have considered physical activity as one element of a multifactorial behavioural intervention, few have focused exclusively on changing sedentary behaviour. Overall, current results are encouraging and it appears that response to an internet-based physical activity intervention is similar to response to other more established, effective interventions. Given that primary care referrals for physical activity are successful in changing sedentary behaviour to some extent, there is an urgent need for investigations into the effect of using an internet-based physical activity programme within the context of primary care. Although no studies that have combined an established internet-based physical activity programme with primary care were found, there is evidence that significant progress would probably be made by providing clinicians with information on internet-based physical activity programmes.
HYPERSPECTRAL IMAGING USING CHROMOTOMOGRAPHY: A FIELDABLE VISIBLE INSTRUMENT FOR TRANSIENT EVENTS
Authors: BOSTICK RANDALL L. , PERRAM GLEN P.
Published: December 2008

A visible, hyperspectral imager using chromotomography CT) has been built, with the goal of extending the technology to spatially extended sources with quickly varying (> 10 Hz) features, such as bomb detonations and muzzle flashes. Even with a low dispersion, ~0.7 mrad/nm, direct vision prism with undeviated wavelength near λ = 548 nm , spectral resolution of better than Δ λ < 10 nm across the λ = 400 – 600 nm band is demonstrated with spatial resolution of better than 0.5 mm. The primary objective of this paper is to show empirically that the spatial and spectral resolution of data obtained by a simple CT instrument is unchanged in projection space and reconstructed object space.
DISCRIMINATION BETWEEN NATURAL DENSE DUST CLOUDS WITH IR SPECTRAL MEASUREMENTS
Authors: AGASSI EYAL , RONEN AYALA , SHILOAH NIR , HIRSCH EITAN
Published: December 2008

Heavy loads of aerosols in the air have considerable health effects in individuals who suffer from chronic breathing difficulties. This problem is more acute in the Middle-East, where dust storms in winter and spring transverse from the neighboring deserts into dense populated areas. Discrimination between the dust types and association with their source can assist in assessment of the expected health effects. A method is introduced to characterize the properties of dense dust clouds with passive IR spectral measurements. First, we introduce a model based on the solution of the appropriate radiative transfer equations. Model predictions are presented and discussed. Actual field measurements of silicone-oil aerosol clouds with an IR spectro-radiometer are analyzed and compared with the theoretical model predictions. Silicone-oil aerosol clouds have been used instead of dust in our research, since they are composed of one compound in the form of spherical droplets and their release is easily controlled and repetitive. Both the theoretical model and the experimental results clearly show that discrimination between different dust types using IR spectral measurements is feasible. The dependence of this technique on measurement conditions, its limitations, and the future work needed for its practical application of this technique is discussed.
EYE SAFE POLARIZATION DIVERSITY LIDAR FOR AEROSOL STUDIES: CONCEPT DESIGN AND PRELIMINARY APPLICATIONS
Authors: FOCHESATTO JAVIER , COLLINS RICHARD L. , SASSEN KENNETH , QUANTZ HEATHER , GANAPURAM KRISHNAKANTH
Published: December 2008

The concept design and preliminary applications of a new Eye Safe Polarization Diversity Lidar (ESPDL) instrument are described. The lidar operates with polarization diversity in the laser emission and polarization discrimination in the receiver at 1574 nm for tropospheric aerosol studies in the Arctic atmosphere. This instrument was originally designed to operate in the eye-safe wavelength range with a one-channel receiver and 20 dB linear polarization accuracy in the laser emission, and assembled in a compact optical bench. The instrument was upgraded for polarization diversity laser emission, i.e polarization selectivity better than 30 dB, and for linear polarization reception discrimination, i.e. polarization discrimination better than 50 dB. Geophysical lidar applications under the scope of this instrument with an overall instrumental polarimetric accuracy better than 0.1% focus on the identification of very dilute suspended aerosols in the troposphere, ice in-cloud initiation and aerosol/water interfaces, complex aerosols, sub-visible high altitude clouds and environmental issues and dynamic processes in the Arctic such as ice fog, forest fire, and a multilayered stably stratified Arctic boundary layer. In this article we describe the instrument design concept and the electronic synchronization necessary to achieve the maximum instrumental polarization accuracy. We report a preliminary case study of differential polarization analysis.
INFINIBAND ROUTING TABLE OPTIMIZATIONS FOR SCIENTIFIC APPLICATIONS
Authors: KERBYSON DARREN J. , LANG MIKE , JOHNSON GREGORY
Published: December 2008

The achievable performance on Infiniband networks is governed by the latencies and bandwidths of communication channels as well as by contention within the network. Currently Infiniband uses static routing to transfer messages and thus does not take into account dynamic loading of the channels. By interrogating the network routing tables we quantify the contention that occurs for a number of communication patterns using a large-scale (1024 processor) system. Empirical data confirms our contention calculation almost exactly. Custom routing tables are defined that provide both optimum and worst-case performance for a large-range of communication patterns. Performance differences can be as large as 12× (from optimum to worst-case). Two large-scale applications show a run-time improvement of between 10-20% and up to a 40% improvement in just their communication time when using optimized routing tables. The approach taken is applicable to many Infiniband systems, and we expect the performance improvements to be even greater on larger-scale systems.
Estimation of quality for software components
Authors: Sharma Arun , Kumar Rajesh , Grover P. S.
Published: December 2008

Component-Based Development (CBD) approach now is widely accepted in software industry. This approach enables efficient application development through the integration of already developed software components. The success of these applications heavily depends upon the selection of appropriate components to fit customer requirements. Therefore it is very necessary to evaluate the quality of components before using them in the final system. Quality models proposed so far can not be fully implemented as-it-is on components and component-based systems (CBS) due to architectural differences in the development approach. Present paper surveys a number of quality models for traditional and component-based systems and proposes a new model for CBS by proposing some new characteristics, which may be very relevant in the context of components. All the quality characteristics may not be of prime importance for an application to be developed for a specific domain. Therefore, it is necessary to identify only those characteristics/sub-characteristics, which may have higher priorities over the others. The present work uses Analytical Hierarchy Process (AHP) to assign the weight values to the characteristics for the proposed model. These weight values are then used to evaluate the quality contribution of sub-characteristics, characteristics and then finally the overall quality of the component by using the appropriate metrics. This approach can be used to identify and select better quality component among several others which can be used in the final system.
Growth of Yersinia pseudotuberculosis in human plasma: impacts on virulence and metabolic gene expression
Authors: Rosso Marie-Laure , Chauvaux Sylvie , Dessein Rodrigue , Laurans Caroline , Frangeul Lionel , Lacroix Céline , Schiavo Angèle , Dillies Marie-Agnès , Foulon Jeannine , Coppée Jean-Yves , Médigue Claudine , Carniel Elisabeth , Simonet Michel , Marceau Michaël
Published: December 2008

Background

In man, infection by the Gram-negative enteropathogen Yersinia pseudotuberculosis is usually limited to the terminal ileum. However, in immunocompromised patients, the microorganism may disseminate from the digestive tract and thus cause a systemic infection with septicemia.

Results

To gain insight into the metabolic pathways and virulence factors expressed by the bacterium at the blood stage of pseudotuberculosis, we compared the overall gene transcription patterns (the transcriptome) of bacterial cells cultured in either human plasma or Luria-Bertani medium. The most marked plasma-triggered metabolic consequence in Y. pseudotuberculosis was the switch to high glucose consumption, which is reminiscent of the acetogenic pathway (known as "glucose overflow") in Escherichia coli. However, upregulation of the glyoxylate shunt enzymes suggests that (in contrast to E. coli) acetate may be further metabolized in Y. pseudotuberculosis. Our data also indicate that the bloodstream environment can regulate major virulence genes (positively or negatively); the yadA adhesin gene and most of the transcriptional units of the pYV-encoded type III secretion apparatus were found to be upregulated, whereas transcription of the pH6 antigen locus was strongly repressed.

Conclusion

Our results suggest that plasma growth of Y. pseudotuberculosis is responsible for major transcriptional regulatory events and prompts key metabolic reorientations within the bacterium, which may in turn have an impact on virulence.
TCF7L2variant genotypes and type 2 diabetes risk in Brazil: significant association, but not a significant tool for risk stratification in the general population
Authors: Marquezine GF , Pereira AC , Sousa AGP , Mill JG , Hueb WA , Krieger JE
Published: December 2008

Background

Genetic polymorphisms of the TCF7L2 gene are strongly associated with large increments in type 2 diabetes risk in different populations worldwide. In this study, we aimed to confirm the effect of the TCF7L2 polymorphism rs7903146 on diabetes risk in a Brazilian population and to assess the use of this genetic marker in improving diabetes risk prediction in the general population.

Methods

We genotyped the single nucleotide polymorphisms (SNP) rs7903146 of the TCF7L2 gene in 560 patients with known coronary disease enrolled in the MASS II (Medicine, Angioplasty, or Surgery Study) Trial and in 1,449 residents of Vitoria, in Southeast Brazil. The associations of this gene variant to diabetes risk and metabolic characteristics in these two different populations were analyzed. To access the potential benefit of using this marker for diabetes risk prediction in the general population we analyzed the impact of this genetic variant on a validated diabetes risk prediction tool based on clinical characteristics developed for the Brazilian general population.

Results

SNP rs7903146 of the TCF7L2 gene was significantly associated with type 2 diabetes in the MASS-II population (OR = 1.57 per T allele, p = 0.0032), confirming, in the Brazilian population, previous reports of the literature. Addition of this polymorphism to an established clinical risk prediction score did not increased model accuracy (both area under ROC curve equal to 0.776).

Conclusion

TCF7L2 rs7903146 T allele is associated with a 1.57 increased risk for type 2 diabetes in a Brazilian cohort of patients with known coronary heart disease. However, the inclusion of this polymorphism in a risk prediction tool developed for the general population resulted in no improvement of performance. This is the first study, to our knowledge, that has confirmed this recent association in a South American population and adds to the great consistency of this finding in studies around the world. Finally, confirming the biological association of a genetic marker does not guarantee improvement on already established screening tools based solely on demographic variables.
Activating and inhibiting connections in biological network dynamics
Authors: McDonald Daniel , Waterbury Laura , Knight Rob , Betterton M D
Published: December 2008

Background

Many studies of biochemical networks have analyzed network topology. Such work has suggested that specific types of network wiring may increase network robustness and therefore confer a selective advantage. However, knowledge of network topology does not allow one to predict network dynamical behavior – for example, whether deleting a protein from a signaling network would maintain the network's dynamical behavior, or induce oscillations or chaos.

Results

Here we report that the balance between activating and inhibiting connections is important in determining whether network dynamics reach steady state or oscillate. We use a simple dynamical model of a network of interacting genes or proteins. Using the model, we study random networks, networks selected for robust dynamics, and examples of biological network topologies. The fraction of activating connections influences whether the network dynamics reach steady state or oscillate.

Conclusion

The activating fraction may predispose a network to oscillate or reach steady state, and neutral evolution or selection of this parameter may affect the behavior of biological networks. This principle may unify the dynamics of a wide range of cellular networks.

Reviewers

Reviewed by Sergei Maslov, Eugene Koonin, and Yu (Brandon) Xia (nominated by Mark Gerstein). For the full reviews, please go to the Reviewers' comments section.
Thalidomide influences growth and vasculogenic mimicry channel formation in melanoma
Authors: Zhang Shiwu , Li Man , Gu Yanjun , Liu Zhiyong , Xu Shaoyan , Cui Yanfeng , Sun Baocun
Published: December 2008

Aims

To observe the effects of thalidomide on melanoma tumor growth and blood supply patterns in C57 mice.

Methods

Thirty mice inoculated subcutaneously with B16F10 cells were randomly divided into the treatment group and the control group. Thalidomide was administered once a day at a dose of 200 mg/kg for the treatment group starting on the fifth day after inoculation, and an equivalent volume of 0.5% carboxylmethyl cellulose was administered similarly in the control group. The diameter of the tumors was measured daily after inoculation until the mice were sacrificed on the 19th day. The different blood supply patterns were counted after immunohistochemical and PAS histochemical double-Staining. VEGF, NF-κB, PCNA, MMP-2 and MMP-9 expression in tumor tissue was also assessed.

Results

The tumor volume(P = 0.019) and the number of vasculogenic mimicry(P = 0.03) and mosaic vessels(P = 0.004) in the treatment group were significantly decreased compared with the control group. VEGF(P = 0.004), NF-κB(P = 0.009), PCNA(P = 0.002), MMP-2 (P = 0.000), MMP-9(P = 0.002) protein expression and MMP-2(P = 0.000) and MMP-9(P = 0.000) mRNA in the treatment group were significantly lower than those in the control groups.

Conclusion

Thalidomide inhibits vasculogenic mimicry channel and mosaic vessels formation in melanoma through the regulation of vasculogenic factors, and it can induce necrosis of melanoma cells, which may be related with the NF-κB signaling pathway.
The Truman-Churchill Proposal to Resolve the Iran-U.k. Oil Nationalization Dispute
Authors: Pirouz Kamrouz
Published: December 2008

After becoming prime minister for the second time, and having won the oil nationalization case at the World Court, Muhammad Musaddiq was hopeful that the British would be more compromising in their approach toward the oil nationalization issue. He was also hopeful of the American support in the dispute.

President Truman and Secretary of State Dean Acheson were both sympathetic toward Iran. At the same time Churchill, who had just become prime minister, was concerned about maintaining American support in this crisis. The mutual efforts of the British and Americans to reconcile their objectives finally led to a joint proposal issued by Truman and Churchill. This proposal spelled out the basis for a new agreement regarding the oil nationalization dispute. This proposal was rejected by Musaddiq's government. The two leaders subsequently issued a second proposal that was also rejected by Musaddiq's government. With this second rejection the Americans and British concluded that they could not resolve the oil issue through negotiation with Musaddiq.
Sterols and lignin in Eucalyptus globulus Labill. wood: Spatial distribution and fungal removal as revealed by microscopy and chemical analyses
Authors: Speranza Mariela , Gutiérrez Ana , del Río José Carlos , Bettucci Lina , Martínez Ángel T. , Martínez María Jesús
Published: December 2008

Wood decay experiments were carried out aiming at the selective removal of lipophilic compounds with selected basidiomycetes isolated from Eucalyptus globulus plantations in Uruguay: Dendrophora albobadia, Lentinus tigrinus, Peniophora cinerea, Peniophora lycii, and Phanerochaete crassa. Localization and composition of lipophilic compounds and lignin of E. globulus were determined by gas chromatography-mass spectrometry, fluorescence microscopy using filipin staining, confocal laser scanning microscopy (CLSM), and low temperature scanning electron microscopy. Free and esterified sterols, mainly sitosterol, were the predominant lipophilic compounds in the control wood. Sterols were present in ray parenchyma cells, together with polyphenols, and in vessels. This confirms earlier observations indicating that these cell types are the principal source of lipophilic extractives involved in pitch problems during pulping and bleaching. Sterols are also present in the vestures of fiber and vessel pits. Different fungal degradation patterns of E. globulus wood were determined. P. lycii showed the highest specificity for lignin degradation during short incubation time together with considerable sterol removal capacity. Ray parenchyma cells and their lumen deposits were strongly degraded by P. lycii. Eucalypt lignin located in vessel walls and fiber cell corners was more resistant to fungal attack, as revealed by CLSM. The initial decay stage of L. tigrinus was restricted to vessels and tyloses where the sterol compounds were removed.
Impact of USA-Euratom Cooperative Dosimetry Research on NRC Regulation of Light Water Reactors
Authors: Serpan CZ
Published: December 2008

Lifetime predictions of the safe condition of reactors, especially the reactor pressure vessel, are based on trends developed from surveillance program tests of metallurgical specimens representing the vessel steel and by analysis of neutron dosimetry detector materials. Although metallurgical characteristics have been studied in great detail since the late 1950s, only since the mid-1970s has there been a dedicated and effective program to set an accurate basis for light water reactor (LWR) neutron dosimetry. With the startup of the Nuclear Regulatory Commission (NRC) Surveillance Dosimetry Improvement Program, the joining of forces with the Euratom Working Group on Reactor Dosimetry (WGRD), and the founding of the ASTM-Euratom Symposia on Reactor Dosimetry, a significant advance of technology for prediction and measurement of neutron flux, fluence, and spectra in LWR environments was assured. The NRC has been well served by this cooperative program, in that we depend upon the improved dosimetry results as the basis upon which we gain assurance of the accuracy and reliability of submittals involving neutron flux and fluence for a range of issues that include surveillance program analysis, pressurized thermal shock, Regulatory Guide 1.99, “Radiation Embrittlement of Reactor Vessel Materials,” and most recently for core internals. Metrology of the neutron flux in power reactors has come a long way in the last decade in terms of accuracy and reliability; maintenance of that accuracy and reliability will be necessary for the future as utilities begin to apply for license renewal for an additional period of operation. Continued safe operation of nuclear power plants will be dominated by knowledge of vessel embrittlement and that, in turn, will be greatly influenced by the accuracy of neutron dosimetry.
Recent Improvement in Vessel Surveillance Dosimetry for the Electricité de France Reactors under Construction
Authors: Bevilacqua A , Brillaud C , DuQuesne H , Hedin F , Lloret R
Published: December 2008

In the vessel surveillance program of each French pressurized water reactor, four to eight in-reactor irradiation capsules are equipped with activation and fission dosimeters. From the analysis of the first capsules irradiated, considerable experimental data are now available on the dosimetry technique used, based on the experience of more than fifteen Electricité de France 900 MWe reactors.

This paper discusses the problems encountered after dismantling the capsule: activity measurements, data corrections, inconsistency of results, etc. From these experimental results, proposals are made to improve accuracy, availability, and ease of use, for short and long term applications. This analysis has led to a better specification of material composition with respect to impurities and, as a result, to changes in the number, design, and materials of both the fissile dosimeter box and the neutron filter. Also, niobium dosimetry has been added to the set of dosimeters.
Nuclear Plant Life Extension
Authors: Negin CA
Published: December 2008

This paper provides a summary of the current efforts in the United States to extend nuclear reactor plant lives beyond the initial licensed terms. The preliminary results of studies to date indicate that plant life extension is feasible, from both economic and safety viewpoints.
Solid-State Track Recorder Pressure Vessel Surveillance Neutron Dosimetry at Commercial Light Water Reactors
Authors: Ruddy FH , Seidel JG
Published: December 2008

Solid-state track recorder (SSTR) neutron dosimetry sets have been installed in the reactor cavity region of several commercial light water reactors for exposures during normal operating cycles. Analyses of SSTR sets which have been exposed for one operating cycle at four commercial light water reactors have been completed. Quality assurance procedures are in place and have been verified with neutron irradiations of representative dosimeters in NBS benchmark neutron fields.

Cavity dosimetry results to date indicate that 2 to 5% uncertainties in the measurements of neutron-induced cavity dosimetry fission rates are routinely achievable, provided that adequate quality control procedures are used.
Measurement of the 93Nb(n,n′) Fission Spectrum Cross Section
Authors: Williamson TG , Ayers TA , Hammersten WL , Lamaze GP , Schima FJ
Published: December 2008

Niobium foil materials were irradiated in the cavity fission source of the National Bureau of Standards Reactor. The foils were counted directly with a germanium low-energy spectrometer (LEPS). A Monte Carlo code was written to calculate the number of X-rays at the detector for each disintegration. The measured cross section for the reaction 93Nb(n,n′)93mNb is 144 ± 5 mb.
Nuclear Data Problems Encountered in Reactor Neutron Metrology
Authors: Zijp WL , Debertin K
Published: December 2008

A review is given of nuclear data problems encountered in activity measurements for reactor neutron dosimetry, as observed in the Euratom Working Group on Reactor Dosimetry and its subgroup on nuclear data. The situation with respect to decay data, cross sections, and fission yields is discussed. Special attention is paid to the treatment of inconsistent data sets and to the role of covariances.
On the Problems Encountered in Activation Spectrometry and Subsequent Radiation Damage Predictions
Authors: Zijp WL , Zsolnay ÉM , Nolthenius HJ , Szondi EJ
Published: December 2008

An international calculation exercise REAL-84 was carried out in order to provide data for the assessment of uncertainty values in radiation damage predictions with neutron spectrum adjustment procedures. The input data of the exercise consisted of good quality input information. The emphasis of the exercise was concentrated on the characterization of radiation damage for reactor pressure vessels and related nuclear technology. Twelve different laboratories participated in the exercise. The evaluation of the results of the exercise led to a number of observations and suggestions for improvement of neutron metrology procedures.
Role of Covariances in Reactor Dosimetry
Authors: Goulo V
Published: December 2008

A review of the International Atomic Energy Agency (IAEA) Nuclear Data Section activity on covariance data production and processing, status of the International Reactor Dosimetry File ( IRDF). and the role of covariance information for radiation damage predictions is presented. The role of international cooperation in improving covariance data and their use is discussed.
Derivation of Neutron Exposure Parameters from Threshold Detector Measurements
Authors: Grundl J
Published: December 2008

A procedure will be outlined which is appropriate for threshold detector measurements that have limited uncertainty information and/or are benchmark referenced. The derivation focuses on individual detector results and the option of coarse group spectrum adjustment when observed spectral indexes are in modest disagreement with the prediction of an a priori neutron spectrum of unknown accuracy. Characteristics of the procedure include a simple choice of error components, exclusion of intrinsic spectrum interpolations, and an explicit diagnosis of the effect upon the adjustment of individual detector response parameters. A sample problem is worked out in detail.
Détermination de fonctions de dommages pour les matériaux polyatomiques irradiées en réacteurs de recherche
Authors: Alberman A , Lesueur D
Published: December 2008

L'évaluation des paramètres d'irradiation de matériaux polyatomiques est d'une grande importance pour les programmes de technologie de la fusion contrô lée. Les céramiques — particuliérement pour la couverture fertile — font actuellement l'objet de programmes d'études dans les réacteurs de recherche européens.

On présente le code COMPOSI: calcul du nombre de déplacements d'atomes du sousréseau “j” induits par un atome du sous-réseau “i” soit par collision directe, soit par processus indirect (atome choqué intermédiaire). Ce calcul, fondé sur les équations de Lindhard, est résolu par une méthode itérative.

Les sections efficaces de déplacements d'atomes “j”, selon l'énergie de neutron, sont déduites par convolution avec les spectres d'énergie de primaires de type “i”. En outre, le code COMPOSI permet de calculer directement les déplacements créés par le recul de particules chargées, exemple Alpha + Triton créés par capture sur le Lithium 6 dans LiAlO2. On teste la sensibilité des fonctions de dommage dans différents spectres neutroniques.
Constant Chemistry Analysis (CCA) Approach to Predicting Transition Temperature Shift in Pressure Vessel Steels under Neutron Irradiation
Authors: Maricchiolo C , Milella PP , Pini A
Published: December 2008

A revision of the ENEA equation for predicting radiation damage of A533 and A508 steels is presented. Constant Chemistry Analysis (CCA), as in the previous work, has been adopted to reduce experimental data but a larger collection of data has been used. Damage is quantified through the increase in transition temperature,ΔT, which takes the form:ΔT = CF.fn, where CF (chemistry factor) and n are copper and nickel content dependent and f is the fluence. Steels considered in the analysis are A533 and A508 irradiated in test reactors with a Cu content ranging between 0.02 and 0.24% and Ni content ranging between 0.4 and 1.6%. The irradiation temperature was around 290°C, and the fluence varied from 1 to 9.1019 n/cm2. The main conclusion of the present analysis is that saturation, for the considered steels, does not take place at high fluence.
Intercomparison of Activity Measurements in Different Laboratories on a Set of Monitor Foils Irradiated in a Spallation Neutron Spectrum
Authors: Alberts WG , Cesana A , D'hondt P , Dierckx R , Hegedüs F
Published: December 2008

A set of monitor foils composed of Ti. Fe, Ni, Co, Au, and Nb was irradiated for three months at the LAMPF beam stop with a neutron fluence of approximately 2 . 1019 cm-2. The activities of a representative selection of these foils were determined in an inter-laboratory comparison. The participating laboratories (CESNEF, PTB, SCK/CEN, and EIR) used their established measuring procedures. The methods are described briefly; apparent differences in the results and possible reasons for them are discussed.
Correction of Burn-In Effects in Fission Neutron Dosimeters
Authors: Gold R , McElroy WN
Published: December 2008

When fission neutron dosimeters are applied for neutron dosimetry, such as those used in light-water reactor (LWR) pressure vessel surveillance (PVS), higher order actinide isotopes can be produced in the dosimeter by the neutron field. These higher order actinide isotopes can also undergo fission and thereby contribute to the number of fissions or fission rate that is observed with the dosimeter. This so-called "burn-in" effect can be non-negligible, especially in fission threshold monitors such as those used in LWR-PVS.

A novel method for correction of this "burn-in" effect is advanced. In this new method, two quantities are measured in order to quantify the "bum-in" contribution, namely the amount of the "in-grown" fissile isotope that is created and the fissions per unit volume produced in the "in-grown" fissile isotope. Monitors used to measure these two quantities must experience the very irradiation that the fission neutron dosimeter undergoes, (i.e., the same location and flux-time history). Conditions are defined under which the "burn-in" effect can be delineated in terms of these two observed quantities. Advantages of this correction method are discussed.
Analysis of Neutron Emission on PWR Spent Fuel Assemblies for Burn-Up Assessment
Authors: Debrue J , Raedt CD , Minsart G
Published: December 2008

A series of passive neutron measurements performed on TIHANGE I spent fuel assemblies were analyzed for comparison with calculated burn-up values and neutron emission rates. The burn-up range of these assemblies was between 10 and 45 MWd/kg and the cooling time varied from 1 to 8 years approximately.

The measurements, performed with 235U fission chambers, were correlated with neutron emission and burn-up by means of the ORIGEN-2 point model depletion code, taking into account the irradiation history. A fairly good correlation was found between the 244Cm contributions, as deduced from the measurements corrected with ORIGEN-2, and the burn-up values as calculated with fuel management codes. It was noticed that the ratio of the calculated (ORIGEN-2) neutron emission and the measured neutron detection varied with the burn-up.
Self-Powered Neutron Detectors for Measuring Epithermal Neutron Flux
Authors: Agu MN , Petitcolas H
Published: December 2008

Self-powered neutron detectors (SPNDs) with erbium, hafnium, gadolinium, rhodium, silver, and cobalt emitters have been irradiated in several different neutron and gamma spectra obtained by a variety of filters: cadmium, gadolinium, boron, lead, zirconium, aluminum, or light water. The irradiation locations were inside the core or reflector of the MELUSINE (8 MW) and SILOE (35 MW) reactors.

Fast and delayed sensitivities to thermal and epithermal neutron and gamma-ray fluxes have been evaluated. Measurements show that gamma and epithermal neutron currents are of the same order of magnitude. It became possible, however, to drive down to zero the gamma sensitivity by laying one or several shroudings onto the emitter surface. This shrouding may now be optimized in order to reduce the SPND's response time.
Factors That May Affect the Results of Indoor Air Quality Studies in Large Office Buildings
Authors: Seppänen O , Jaakkola J
Published: December 2008

The effects of mechanical ventilation on the sick building syndrome were evaluated in an office building with 2150 employees. The ventilation rate was known to be high in the building. The main hypothesis put forward was that reducing the rate of mechanical ventilation would alleviate symptoms. A short-term trial was carried out by shutting off the ventilation in one part of the building, reducing it in two areas and leaving one part unalteredas a control. The reduction of ventilation had, if any, an opposite effect to that anticipated. There was a linear correlation between increase in symptoms and rise in room temperature to above 22°C.

Many complaints about drafts occurred even though the measured average velocities were only 0.05 m/s. Ventilation rates per person varied greatly depending on the location in the building and on the number of persons in a room. The variation of the temperature between the rooms was large. Tobacco smoke bothered people although smoking was not allowed in the offices.

In the analysis of the data many confounding variables were found. Women expressed their symptoms almost twice as often as men. The age, allergic disposition, and overall job satisfaction had also a significant effect on the symptoms. These factors were controlled in the analysis.

Based on the study, temperature seems to be the most important variable in indoor climate and it should be individually controlled.
The NIOSH Approach to Conducting Indoor Air Quality Investigations in Office Buildings
Authors: Gorman RW , Wallingford KM
Published: December 2008

Since 1971, personnel from the National Institute for Occupational Safety and Health (NIOSH) have completed approximately 450 indoor air quality (IAQ) investigations in a variety of office building environments. Most of these investigations have been conducted since 1979, paralleling the energy conservation concerns of building owners and operators. These investigations have been conducted under the authority of the NIOSH Health Hazard Evaluation Program and have been in direct response to reported health complaints or illness. Therefore these IAQ investigations are intended to establish the identity of a problem and to recommend solutions for its correction. Over time, we have developed a consistent methodology with a “solution-oriented” approach to conducting these IAQ investigations. To initiate the investigation, the NIOSH team gathers background information by telephone and then makes a site visit to interview the affected employees and establish symptom identity and prevalence. During this initial site visit, the investigators also attempt to identify sources of contaminants, evaluate comfort parameters, and assess ventilation system performance. A variety of applicable evaluation criteria may be used, including "rules-of-thumb" gleaned from the current scientific literature and our own experiences. If specific problems cannot be identified through these initial means, follow-up visits are then used to pursue a continually narrowing range of possibilities. This “solution-oriented” approach has resulted in the best allocation of our resources and has allowed the most efficient use of in-field as well as analytical personnel. In the IAQ investigations completed to date, problems were found to result from building material contaminants in 3%, microbiological contaminants in 5%, contaminants brought in from outside the building in 11%, contaminants from inside the building in 17%, and inadequate ventilation problems in 52%. The remaining 12% represent those investigations where no problem could be identified.
Workshop: Designing Indoor Air Quality Survey Studies
Authors: Kollander M , Whitmore R , Wallace L , Brenner FC
Published: December 2008

Major design considerations of indoor air quality survey research studies con-ducted in the United States over the past seven years are examined.
Progress in the Development of a Wave Action Standard History (WASH) for Fatigue Testing Relevant to Tubular Structures in the North Sea
Authors: Pook LP , Dover WD
Published: December 2008

Fixed tubular steel platforms were first installed in the North Sea in 1966. They are subjected to significant fatigue loads due to wave action, and consequently a large number of relevant fatigue tests have been carried out on representative tubular joints. In 1979, the Wave Action Standard History (WASH) Working Group was formed to develop standard load spectra for fatigue testing relevant to offshore structures. This paper reviews some of the work that has been carried out in support of the Working Group, but it is not an official Working Group document. It is concluded that construction of realistic load spectra representative of wave loading on tubular structures in the North Sea is feasible at the current state of the art. The basic steps needed for implementation of a tentative standard load spectrum are described.
Compilation of Procedures for Fatigue Crack Propagation Testing Under Complex Load Sequences
Authors: Sunder R
Published: December 2008

A review is made of procedures, developed at the National Aeronautical Laboratory for fatigue crack propagation testing under flight spectrum loading. They include K-control and on-line spectrum editing that were found to have a significant impact on spectrum load testing. Techniques are described for unambiguous assessment of crack closure stress and for binary-coded marker loading.