bluuebunny/crossref_metadata_2025 huggingface dataset:
MOX Fresh Fuel Packaging: Status of Full Scale Prototype Testing
Authors: Field J. G. , Nichols J. C. , Noss P. W.
Published: August 2008

Packaging Technology, Inc. is designing the Mixed Oxide (MOX) Fresh Fuel Package (MFFP) for Duke Cogema Stone & Webster (DCS). The package is unique because of weight and size constraints, having a relatively large payload to package weight ratio. The package has a containment shell, that utilizes high strength stainless steel to optimize the payload relative to the total weight available, protected at the ends by impact limiters. Because of the unique design, full scale prototype impact testing is scheduled for mid-2003. Engineering testing on key design elements, and certification test planning have been completed. Long lead material has been procured for fabrication of the prototype.
Gamma Scan Confirmation of Lead Pour in a Type B Cask
Authors: Migliore R. J. , Field J. G. , Hillstrom D. S. , Johnson R. A.
Published: August 2008

Packaging Technology, Inc., a subsidiary of the French nuclear consortium Areva, has been tasked with manufacturing six RH-72B (72B) casks for the Department of Energy’s Carlsbad Operations Office. The 72B transportation cask will be used to transport remote-handled (RH) transuranic wastes to the Waste Isolation Pilot Plant (WIPP) located in New Mexico. Certification of each 72B cask includes a gamma scan of the cask lead shielded wall to verify that no significant voids form within the lead subsequent to the lead pour. Voids in the lead would be revealed as spikes in the gamma scan measurements. The radioactive isotope Iridium-192 was used as the source for the gamma scan measurements. To determine the maximum and minimum expected values for the cask gamma scan, a test fixture was required to be developed with flat plate shields that matched the maximum and minimum thicknesses of the steel-lead-steel cask wall. Design of the test fixture was a non-trivial exercise due to the influence of backscatter radiation, which if unshielded resulted in unreasonably high test fixture radiation doses. To properly shield the backscatter radiation, a collimator is required around the source. The measured dose rates using the test fixture is highly sensitive to the diameter of the collimator penetration, as a collimator penetration diameter that is too narrow results in artificially low dose rate measurements when compared to the cask measurements. To assist in the design of the collimator, the Monte Carlo N-Particle (MCNP) gamma transport code was employed. Using MCNP computer simulations, it was determined that a collimator diameter of 6 inches was sufficient to properly mimic the cask configuration.
Digital Radiography vs Conventional Radiography: Is Digital Radiography in Compliance With the Code?
Authors: Poland Richard W. , Immel David M. , Howard Boyd D.
Published: August 2008

Savannah River Technology Center filmless radiographic imaging system specialists have been “champions” of filmless radiographic imaging at the Savannah River Site since 1993. Recently a study was done comparing the differences between conventional film radiography and lens-coupled, charge-coupled-device digital radiography. Characteristics of both imaging methods that were considered in the study included resolution, latitude (called dynamic range by digital radiography imaging specialists), and modulation transfer functions. The results of those comparative experiments will be presented. A description of the lens-coupled, digital radiography imaging system will be provided.
Quantitative NDT and Fitness for Purpose
Authors: Moles M. D. C. , Ginzel E. , Dube´ N.
Published: August 2008

The concepts of Fitness for Purpose (FFP), now popular in engineering, have placed greater demands on Non-Destructive Testing/Evaluation (NDT) to provide quantitative results. No NDT method seems better adapted to provide quantitative results than ultrasonic testing. However, acceptance criteria presented to the ultrasonic operator are sometimes difficult to comply with, as they seem not to consider the limitations and tolerances intrinsic in the techniques used. Overly optimistic expectations of sizing accuracy could result in under-sizing of flaws, but overly stringent acceptance criteria to “compensate” for sizing errors can result in more repairs than would be required by radiographic workmanship acceptance criteria in spite of much higher detection rates by ultrasonic methods. This paper considers some ultrasonic sizing techniques and their associated accuracies and application limitations. Examples from early work in Time-Of-Flight Diffraction (TOFD) and tip diffraction are considered as well as statistical studies from girth weld inspection techniques.
Phased Array UT Technology for Nuclear Pipe Inspection
Authors: MacDonald Doug E. , Dennis Mark A. , Landrum Jeff L. , Selby Greg P.
Published: August 2008

Phased array UT technologles have been applied to improve pipe inspection speed and reliability. Recent results on similar and dissimilar metal welds show clear, accurate, and fast results. Phased array ultrasound has been developed and commercialized already for high-value, inspections such as turbines and boiling water reactor (BWR) core shrouds. This paper describes how the benefits of phased array technology are being extended for application to piping examinations, including the detection and length sizing of intergranular stress corrosion cracking (IGSCC) in austenitic and dissimilar metal welds. The costs associated with pipe inspections contain factors related to the duration and reliability of inspections. The phased array improvements in flaw detectability, sizing accuracy, and speed, will lower the cost and increase the reliability of piping examinations by reducing qualification costs, radiation exposure, re-scans, and repairs. EPRI is encouraging the deployment of phased array pipe inspection technology by coordinating the technique development with several vendors so that when the technique is qualified, the vendor(s) will be ready to deliver it. This approach has already worked well for other phased array applications. As more vendors develop phased array capabilities, the deployment task becomes easier. To encourage the use of this technology, EPRI has developed and qualified through the Performance Demonstration Initiative (PDI) an automated phased array procedure for piping weld inspection.
In Vitro Imaging Technique of Cell Adhesion
Authors: Dong Chen
Published: August 2008

It is the first object of this article to contribute a side-view imaging technique to investigate adhesion to a surface-immobilized ICAM-1 in shear flow, wherein T-leukemic Jurket cells have been used. A side view image has revealed that the cell adhesion on ICAM-1 under flow conditions in vitro is quasistratic. Changes in flow shear stress, cell deformability, or substrate ligand strength resulted in a significant change in the characteristic adhesion binding time and contact length. The elongation of cells in shear flow tempers hydrodynamic shear forces on the cell, which affects the transients in cell-surface adhesion. It is the second object to calculate a 3-D flow field with shear stress acting on an adherent cell based on the shape of the cell obtained from the image. The application of the side-view imaging technique and the image analysis may provide a practical assay to reveal fundamental behavior of a cell.
Characterization of Thin Biological Tissue With Scanning Acoustic Microscopy
Authors: Miyasaka Chiaki , Du Jikai , Tittmann Bernhard R.
Published: August 2008

The present article reports a technique to measure velocity of a biological specimen, wherein the thickness of the biological specimen and the diameter of the measurement area of the specimen are in the order of a few microns. The kidney was selected for the specimen as an example of the soft material. The kidney was thinly sliced by a microtome and located on a substrate. The thickness of the specimen was substantially 3 μm. For the substrate, fused quartz was used because its elastic properties are known and stable. The spherical acoustic lens was used to determine the position for the measurement. The frequencies of 400 and 600 MHz were used for the measurement and the visualization respectively. The generation of the Rayleigh waves in the above conditions was simulated by numerical calculations based on the wave propagation theory for layered media.
Development in High Frequency Ultrasonic Imaging and Transducers
Authors: Shung K. Kirk
Published: August 2008

There has been intense interest recently in ultrasonic imaging in the frequency range from 20 MHz and beyond in biomedicine. High frequency ultrasound has applications in dermatology, ophthalmology and intravascular imaging because of its superior resolution. The performance of ultrasonic imaging systems especially at high frequencies depends critically upon the transducers/arrays, the design of which in turn is determined to a large degree by the materials and fabrication methodology of the piezoelectric element and supporting structures. Recent developments in these areas are discussed in this paper.
Noninvasive Ultrasound Mediated Transdermal Transport of Insulin Across Ex Vivo Human Skin
Authors: Smith Nadine Barrie , Lee Seungjun , Shung K. Kirk
Published: August 2008

The purpose of this research was to improve low frequency (20 kHz) ultrasound methods for enhancing the transport of insulin across ex vivo human skin. The feasibility of using ultrasound produced by small, lightweight novel transducers was explored for enhancing the transport of insulin across skin. Previous investigators have used ultrasound devices such as large, heavy sonicators or commercially obtained transducers for this type of research. These experiments used two low-profile novel ultrasound transducer arrays, the stack and standard array, for improved transport of insulin. The stack array was driven with a spatial peak temporal peak intensity (Isptp) of 15.5 ± 2.0 mW/cm2 while the standard array had an Isptp of 173.7 ± 9.1 mW/cm2. Spectrophotometeric absorption techniques were used for determining insulin transport across ex vivo human skin. Compared to passive transmission (6.3 ± 14.0 U/hr), the standard array facilitated a 6-fold increase in the noninvasive transdermal transport of Humulin® insulin (39.6 ± 11.7 U/hr). These promising results indicate that low frequency ultrasound can be used in a practical device for enhanced transport across the stratum corneum.
Thermal and Acoustical Insult to Cells as Studied by In-Vivo Acoustic Microscopy
Authors: Tittmann B. R. , Miyasaka C.
Published: August 2008

A plurality of articles discussing combined effects of acoustic high-pressure and heat caused by acoustic vibration on biological tissues and cells has been published. Herein, we contribute the article describing the behavior of living human skin cells when separately applying the pressure and the heat to them. First, for finding the heat effect, we located a container including living human skin cells and a culturing medium on the X-Y stage equipped with the heating plate with temperature controller of the Scanning Acoustic Microscope (SAM). Then, we gradually increased temperature of the culturing medium, and carried out in-situ observation. Second, for finding the acoustic high-power effect, we provided the pressure using high power ultrasonic pulses generated by a laser induced ultrasonic shock wave system to the cells, wherein the pressures caused by the pulses were measured by a hydrophone, and wherein temperature was monitored by thermocouples. The cells were observed with the SAM just after giving the impact. The difference between phenomena indicating cellular insult and injury (e.g., shrinkage or lift-off) were clearly visualized by the SAM with frequency at 1.0 GHz.
Guided Wave Resonance Tuning for Pipe Inspection
Authors: Barshinger James , Rose Joseph L. , Avioli Michael J.
Published: August 2008

Tremendous interest has surfaced recently on the use of guided waves in pipe inspection in the oil, chemical, and power generating industries. Relatively long lengths of piping can be inspected for corrosion and cracking from a single probe position. This saves a great deal of time and money compared to using more standard point-by-point normal beam inspection procedures. Pipes can be inspected without removing insulation or tar coatings by controlling the guided wave modes and frequencies used to carry out the study. This paper will review the history and state of the art of the guided wave techniques in piping. Benefits and limitations of the various methods will be pointed out along with a vision of future directions in the area of pipe and elbow inspection.
Theoretical Approach to Contrast Mechanism for U-AFM
Authors: Miyasaka C. , Tittmann B. R. , Adachi T. , Yamaji A.
Published: August 2008

When the Ultrasonic-Atomic Force Microscope (U-AFM) is used to form an image of a surface of a specimen having discontinuities, contrast of the specimen in the image is usually stronger than that of an image formed by a conventional Atomic Force Microscope (AFM). In this article, the mechanism of the contrast of the image obtained by the U-AFM was explained by theoretical analysis. A ceramic and metal jointed bar (Steel/Cu/Si3N4) was selected as a specimen for this study. The specimen was located on the surface of a disc transducer generating ultrasonic waves up to 500 KHz, and was vibrated, wherein its first resonant frequency was 133.43 kHz. Both stress and displacement of the specimen were analyzed by classical beam theory and the two-dimensional elasto-dynamic theory. Experimental U-AFM imaging analyses were also carried out to compare the results.
Sizing Stress Corrosion Cracking in Natural Gas Pipelines Using Phased Array Ultrasound
Authors: Spanner Jack , Selby Greg
Published: August 2008

Gas transmission pipelines are inspected periodically by robotic systems that pass through the pipe. These inspection systems typically use electromagnetic nondestructive evaluation (NDE) techniques to detect flaws such as stress corrosion cracking (SCC). The electromagnetic techniques can detect and measure the length of the cracks, but cannot measure through wall depths. In some cases it would be desirable to excavate down to a cracked area of the pipe, inspect it “in the ditch” to determine the depth of the cracking, and use the depth information to support repair/replacement decisions. The objective of the research was to develop a nondestructive inspection technique capable of measuring the depth of stress corrosion cracks from the outside surface of a gas transmission pipe in the field. EPRI participated in the round robin study by using a linear phased array technique. Field removed specimens were provided by the Gas Technology Institute (GTI) containing SCC for depth sizing. In most cases sizing was difficult to accomplish because of the colony of cracks that existed. This presentation discusses the results obtained and comparing them to destructive analysis results.
Radiation safety issues with positron‐emission/computed tomography simulation for stereotactic body radiation therapy
Authors: Kearns William T. , Urbanic James J. , Hampton Carnell J. , McMullen Kevin P. , Blackstock A. William , Stieber Volker W. , Hinson William H.
Published: August 2008

Stereotactic body radiation therapy (SBRT) simulations using a Stereotactic Body Frame (SBF: Elekta, Stockholm, Sweden) were expanded to include 18F‐deoxyglucosone positron‐emission tomography (FDG PET) for treatment planning. Because of the length of time that staff members are in close proximity to the patient, concerns arose over the radiation safety issues associated with these simulations. The present study examines the radiation exposures of the staff performing SBRT simulations, and provides some guidance on limiting staff exposure during these simulations. Fifteen patients were simulated with PET/CT using the SBF. Patients were immobilized in the SBF before the FDG was administered. The patients were removed from the frame, injected with FDG, and allowed to uptake for approximately 45 minutes. After uptake, the patients were repositioned in the SBF. During the repositioning, exposure rates were recorded at the patient's surface, at the SBF surface, and at 15 cm, 30 cm, and 1 m from the SBF. Administered dose and the approximate time spent on patient repositioning were also recorded. The estimated dose to staff was compared with the dose to staff performing conventional diagnostic PET studies. The average length of time spent in close proximity to the patient after injection was 11.7 minutes, or more than twice the length of time reported for diagnostic PET staff. That time yielded an estimated average dose to the staff of 26.5mSv per simulation. The annual occupational exposure limit is 50 mSv. Based on dose per simulation, staff would have to perform nearly 1900 SBRT simulations annually to exceed the occupational limit. Therefore, at the current rate of 50–100 simulations annually, the addition of PET studies to SBRT simulations is safe for our staff. However, ALARA (“as low as reasonably achievable”) principles still require some radiation safety considerations during SBRT simulations. The PET/CT‐based SBRT simulations are safe and important for treatment planning that optimizes biologic dose distribution with highly accurate and reproducible target definition.

PACS numbers: 87.57.uk, 87.59.bd
Scatter Correction for Heart SPECT images Using TEW method
Authors: Changizi Vahid , Takavar Abbas , Babakhani Azadeh , Sohrabi Mahdi
Published: August 2008

Radionuclide imaging has the potential to be used in quantitative analysis of the regional function of organs. However, quantification of SPECT images is degraded by many factors such as Compton photon scattering. This could have a destructive effect on clinical reports so it is important to do scatter correction to get better quality SPECT images. We intended to determine how scatter correction with the TEW method can help physicians who look at heart SPECT images, get better reports. This study used the TEW method for scatter correction, which was proposed by Ogawa et al.,(9) using the two narrow windows on either side of the photopeak (20% down and 20% up of the photopeak respectively). Injection of radiopharmaceutical 99mTc was used for medical imaging. In the Shariati Hospital, Tehran, we studied a total of 80 patients with heart disease indications (43 men and 37 women) over the ages of 30–80 years. Contrast and sharpness were considerably improved after scatter correction so physicians could look at defects better. In a few cases scatter correction changed heart defect reports to normal. Using TEW, sensitivity and specificity increased from 86% to 94% and from 61% to 84% respectively. This method was simple to use in clinics.

PACS numbers: 87.57.uh
Evaluation of MVCT images with skin collimation for electron beam treatment planning
Authors: Beardmore Allen B. , Rosen Isaac I. , Cheek Dennis A. , Fields Robert S. , Hogstrom Kenneth R.
Published: August 2008

This study assessed the potential of using megavoltage CT (MVCT) images taken with high density skin collimation in place for electron beam treatment planning. MVCT images were taken using the TomoTherapy Hi‐Art system (TomoTherapy Inc., Madison, WI), and the CT numbers were converted to density by calibrating the Hi‐Art system using an electron density phantom. Doses were computed using MVCT images and kVCT images and compared by calculating dose differences in the uniform dose region , excluding buildup region) and calculating distance‐to‐agreement (DTA) in high dose‐gradient regions (penumbra and distal falloff, 90%–10%). For 9 and 16 MeV electron beams of calculated on a homogeneous CIRS Plastic Water (Computerized Imaging Research Systems Inc., Norfolk, VA) phantom without skin collimation, the maximum dose differences were 2.3% and the maximum DTAs were 2.0 mm for both beams. The same phantom was then MVCT scanned nine times with square skin collimators of Cerrobend on its surface ‐ field sizes of , , and and thicknesses of 6, 8, and 10 mm. Using the Philips Pinnacle3 treatment planning system (Philips Medical Systems, N.A., Bothwell, WA), a treatment plan was created for combinations of electron energies of 6, 9, 12, and 16 MeV and each field size. The same treatment plans were calculated using kVCT images of the phantom with regions‐of‐interest (ROI) manually drawn to duplicate the sizes, shapes, and density of the skin collimators. With few exceptions, the maximum dose differences exceeded and the DTAs exceeded 2 mm. We determined that the dose differences were due to small distortions in the MVCT images created by the high density material and manifested as errors in the phantom CT numbers and in the shape of the skin collimator edges. These results suggest that MVCT images without skin collimation have potential for use in patient electron beam treatment planning. However, the small distortion in images with skin collimation makes them unsuitable for clinical use.

PACS: 87.53.Tf, 87.59.Fm, 87.53.Fs
In‐house auto cutoff sensor device for radiotherapy machine to monitor patient movements
Authors: Senthilkumar S , Ramakrishnan V
Published: August 2008

Radiotherapy is an effective treatment method for cancers. During radiation treatment, a patient must be in the same position from the start to the end of radiation treatment. Patient movements are usually monitored by the radiation technologists through the closed circuit television (CCTV) during treatment. If the patient makes a small movement, it is difficult to be noticed by them. In the present work, a simple patient movement monitoring device (PMMD) is fabricated to monitor the patient movement. It uses an electronic sensing device. It continuously monitors the patient's position while the radiation treatment is in process. The device has been retrospectively tested on 86 patients whose movement and distance were measured. The results show that 24 patients moved 1 cm to 2.5 cm from their initial position during the external beam radiotherapy (EBRT). Hence, the device can potentially be used to control and monitor patient movement during EBRT. In addition, an audible alarm situated at the control panel of the treatment room is provided with this device to alert the radiation technologists. It is an inexpensive, compact device which can be used in any radiotherapy machine. It can prevent patients from being treated in a wrong position and therefore improve the quality of the radiation treatment.

PACS Number: 87.53Dq
Aqueous foam slip and shear regimes determined by rheometry and multiple light scattering
Authors: Marze Sebastien , Langevin Dominique , Saint-Jalmes Arnaud
Published: August 2008

By using simultaneously rheometry and a multiple light scattering technique, diffusing wave spectroscopy (DWS), we have studied the steady flows of three-dimensional aqueous foams. A number of parameters—the surfactants, the liquid volume fraction, and the roughness of the rheometer surfaces—are widely varied in order to determine which quantities have an impact on the macroscopic flow behaviors. By comparing to previous theoretical and experimental results, we show that flow regimes can either be slip or shear dominated. Two opposite slip regimes are identified; the transition from one to the other is obtained either by changing the surfactant or the liquid fraction, and we quantitately discuss which regime is selected for any given foam properties. Similarly, different shear regimes are also found, and we discuss the link between the macroscopic rheometry measurements, the nature of the flow, and the interfacial microscopic properties. Despite the occurrence of slip, we show how we can recover the actual shear rate by DWS, and how we can quantitatively explain the measured slip velocities.
Adaptation of Aerobically GrowingPseudomonas aeruginosato Copper Starvation
Authors: Frangipani Emanuela , Slaveykova Vera I. , Reimmann Cornelia , Haas Dieter
Published: August 2008

Restricted bioavailability of copper in certain environments can interfere with cellular respiration because copper is an essential cofactor of most terminal oxidases. The global response of the metabolically versatile bacterium and opportunistic pathogenPseudomonas aeruginosato copper limitation was assessed under aerobic conditions. Expression ofcioAB(encoding an alternative, copper-independent, cyanide-resistant ubiquinol oxidase) was upregulated, whereas numerous iron uptake functions (including the siderophores pyoverdine and pyochelin) were expressed at reduced levels, presumably reflecting a lower demand for iron by respiratory enzymes. Wild-typeP. aeruginosawas able to grow aerobically in a defined glucose medium depleted of copper, whereas acioABmutant did not grow. Thus,P. aeruginosarelies on the CioAB enzyme to cope with severe copper deprivation. A quadruplecyo cco1 cco2 coxmutant, which was deleted for all known heme-copper terminal oxidases ofP. aeruginosa, grew aerobically, albeit more slowly than did the wild type, indicating that the CioAB enzyme is capable of energy conservation. However, the expression of acioA′-′lacZfusion was less dependent on the copper status in the quadruple mutant than in the wild type, suggesting that copper availability might affectcioABexpression indirectly, via the function of the heme-copper oxidases.
Interplay between Cyclic AMP-Cyclic AMP Receptor Protein and Cyclic di-GMP Signaling in
Vibrio cholerae
Biofilm Formation
Authors: Fong Jiunn C. N. , Yildiz Fitnat H.
Published: August 2008

Vibrio cholerae
is a facultative human pathogen. The ability of
V. cholerae
to form biofilms is crucial for its survival in aquatic habitats between epidemics and is advantageous for host-to-host transmission during epidemics. Formation of mature biofilms requires the production of extracellular matrix components, including
Vibrio
polysaccharide (VPS) and matrix proteins. Biofilm formation is positively controlled by the transcriptional regulators VpsR and VpsT and is negatively regulated by the quorum-sensing transcriptional regulator HapR, as well as the cyclic AMP (cAMP)-cAMP receptor protein (CRP) regulatory complex. Transcriptome analysis of
cyaA
(encoding adenylate cyclase) and
crp
(encoding cAMP receptor protein) deletion mutants revealed that cAMP-CRP negatively regulates transcription of both VPS biosynthesis genes and genes encoding biofilm matrix proteins. Further mutational and expression analysis revealed that cAMP-CRP negatively regulates transcription of
vps
genes indirectly through its action on
vpsR
transcription. However, negative regulation of the genes encoding biofilm matrix proteins by cAMP-CRP can also occur independent of VpsR. Transcriptome analysis also revealed that cAMP-CRP regulates the expression of a set of genes encoding diguanylate cyclases (DGCs) and phosphodiesterases. Mutational and phenotypic analysis of the differentially regulated DGCs revealed that a DGC, CdgA, is responsible for the increase in biofilm formation in the Δ
crp
mutant, showing the connection between of cyclic di-GMP and cAMP signaling in
V. cholerae
.
Insights into the Environmental Resistance Gene Pool from the Genome Sequence of the Multidrug-Resistant Environmental Isolate
Escherichia coli
SMS-3-5
Authors: Fricke W. Florian , Wright Meredith S. , Lindell Angela H. , Harkins Derek M. , Baker-Austin Craig , Ravel Jacques , Stepanauskas Ramunas
Published: August 2008

The increasing occurrence of multidrug-resistant pathogens of clinical and agricultural importance is a global public health concern. While antimicrobial use in human and veterinary medicine is known to contribute to the dissemination of antimicrobial resistance, the impact of microbial communities and mobile resistance genes from the environment in this process is not well understood. Isolated from an industrially polluted aquatic environment,
Escherichia coli
SMS-3-5 is resistant to a record number of antimicrobial compounds from all major classes, including two front-line fluoroquinolones (ciprofloxacin and moxifloxacin), and in many cases at record-high concentrations. To gain insights into antimicrobial resistance in environmental bacterial populations, the genome of
E. coli
SMS-3-5 was sequenced and compared to the genome sequences of other
E. coli
strains. In addition, selected genetic loci from
E. coli
SMS-3-5 predicted to be involved in antimicrobial resistance were phenotypically characterized. Using recombinant vector clones from shotgun sequencing libraries, resistance to tetracycline, streptomycin, and sulfonamide/trimethoprim was assigned to a single mosaic region on a 130-kb plasmid (pSMS35_130). The remaining plasmid backbone showed similarity to virulence plasmids from avian-pathogenic
E. coli
(APEC) strains. Individual resistance gene cassettes from pSMS35_130 are conserved among resistant bacterial isolates from multiple phylogenetic and geographic sources. Resistance to quinolones was assigned to several chromosomal loci, mostly encoding transport systems that are also present in susceptible
E. coli
isolates. Antimicrobial resistance in
E. coli
SMS-3-5 is therefore dependent both on determinants acquired from a mobile gene pool that is likely available to clinical and agricultural pathogens, as well, and on specifically adapted multidrug efflux systems. The association of antimicrobial resistance with APEC virulence genes on pSMS35_130 highlights the risk of promoting the spread of virulence through the extensive use of antibiotics.
Gross pathology of the placenta: weight, shape, size, colour
Authors: Kaplan C G
Published: August 2008

The gross examination is critical to making accurate diagnoses on placental specimens. An orderly evaluation of the cord, membranes and villous tissue allows maximal opportunity to recognise abnormalities. Many lesions have a pathognomonic gross appearance, while other processes are best seen on histology. Quantitation of the volume of placental tissue involved in an abnormal process is necessary to distinguish normal variation from significant pathology. Histological sections must include cord, membranes and central villous tissue.
The prevalence and the causes of minimal intestinal lesions in patients complaining of symptoms suggestive of enteropathy: a follow-up study: Table 1
Authors: Biagi F , Bianchi P I , Campanella J , Badulli C , Martinetti M , Klersy C , Alvisi C , Luinetti O , Corazza G R
Published: August 2008

Aims:

Although they are non-specific, minimal intestinal lesions are at the end of the coeliac histological damage spectrum. To investigate whether minimal intestinal lesions in patients without endomysial antibodies are due to coeliac disease, their prevalence, causes and risk of evolving into frank coeliac disease were studied.

Methods:

From January 2000 to December 2005, 645 duodenal biopsies were performed. In 209 patients, duodenal biopsies were performed independently of endomysial antibody results. Clinical data and HLA-typing of all the patients negative to endomysial antibodies but with minimal mucosal lesions were re-evaluated. Three years later, they were offered to be seen again, and further investigations were proposed.

Results:

14 out of 209 patients had minimal mucosal lesions and negative endomysial antibodies. Two patients were lost to follow-up; in 7/12 patients, symptoms and histological lesions were due to a different condition, not related to coeliac disease. In 11/12 patients, HLA-typing made diagnosis of coeliac disease very unlikely. Only one patient was on a gluten-free diet because of gluten-sensitive symptoms and was DQ2+/DQ8+.

Conclusions:

Minimal duodenal lesions in patients negative to endomysial antibodies are rare and are likely to be due to conditions unrelated to coeliac disease.
Arrhenia and Rimbachia, expanded generic concepts, and a reevaluation of Leptoglossum with emphasis on muscicolous North American taxa
Authors: Redhead S. A.
Published: August 2008

The generic limits of Arrhenia Fries, Geotus Pil. & Svr., Leptoglossum Karsten, Leptotus Karst., Mniopetalum Donk & Singer, Phaeotellus Kühn. & Lam., Pleuromycenula Singer, and Rimbachia Patouillard are examined. Two genera, Arrhenia and Rimbachia, are recognized. Keys for the species in these genera are presented and reports of the various species are reevaluated based largely on a restudy of original materials. New combinations in Arrhenia are based on Agaricus fissus Leysser, Merulius lobatus Pers., Helvella retiruga Bull., Leptoglossum alnetorum Singer, and Cantharellus spathulatus Fr. New species combinations in Rimbachia are based on Cyphella arachnoidea Peck, Agaricus bryophilus Pers., Cyphella muscicola var. neckerae Fr., Cantharellus furfuraceus Petch, and Pleuromycenula ellipsoidea Singer. Rimbachia paludosa sp. nov. is described from Ontario, Canada. Leptoglossum muscigenum (Bull.:Fr.) Karst. is a synonym of A.spathulata (Fr.) Redhead, Mniopetalum globisporum Donk & Singer is a synonym of R.arachnoidea (Peck) Redhead, Mniopetalum distinctum Horak is a synonym of R.furfuracea (Petch) Redhead, Leptoglossum candidum Reid is a synonym of R.neckerae (Fr.) Redhead, and Geotus glaucus sensu Pilát & Svrček 1954 is actually A.fissa (Leyss.) Redhead. Mniopetalum bisporum Singer is reduced to a subspecies of R. arachnoidea and Mniopetalum megalosporum Singer to a subspecies of R. neckerae (Fr.) Redhead. In North America, Arrhenia auriscalpium is an arctic–alpine species, A. lobata is an arctic–boreal–alpine species, and A. acerosa and A. retiruga are boreal species. Rimbachia arachnoidea and R. bryophila are boreal species. Arrhenia spathulata and A. fissa are known only from Europe. All Arrhenia and Rimbachia species are bryophiles. Cantharellus polycephalus Bres. is transferred to Pterygellus Corner and Leptoglossum bambusicola Corner is transferred to Marasmiellus Murrill. Pseudocraterellus leptoglossoides Corner is a basidiolichen and the type of a new genus, Semiomphalina Redhead. Pleuromycenula circularis Singer is transferred to Helotium Tode, and P. flava Singer is the type of a new genus, Flabellimycena Redhead. Campanella inquilina Romagnesi, based on Leptoglossum conchatum sensu Romagnesi non Velenovský, is described as new. Cantharellus prescotii Weinm., the correct name for Cantharellus albidus auct. non Fries, is transferred to Gerronema.
Mallomonadacean (Chrysophyceae) assemblages and their relationships with limnological characteristics in 38 Adirondack (New York) lakes
Authors: Smol John P. , Charles Donald F. , Whitehead Donald R.
Published: August 2008

The siliceous scales of 30 mallomonadacean taxa were identified and counted from the surficial sediments of 38 Adirondack lakes. The scales were usually abundant and were always well preserved. The Adirondack flora is typical of acidic to circumneutral oligotrophic lakes. Common taxa include Mallomonas acaroides, M. caudata, M. crassisquama, M. hamata, M. pseudocoronata, M. punctifera, Synura echinulata, S. petersenii, S. sphagnicola, S. spinosa, and Chrysosphaerella longispina. The abundance of certain species (e.g., Mallomonas hindonii, M. hamata) appears to be a reliable indication of acidic waters. Reciprocal averaging (RA) ordination was used to determine if distribution of the mallomonadacean assemblages corresponded with major environmental gradients. Correlations between the first RA axis scores and lakewater pH (r2 = 0.63) and related factors (log10 alkalinity, r2 = 0.66; pCa, r2 = 0.39; pMg, r2 = 0.43) were strongest. Relationships were weaker with average depth, summer epilimnion temperature, elevation, NO3, and total Al, and were not statistically significant with conductivity, color, Secchi disc transparency, total P, chlorophyll a, SO4, and Si. Cluster analysis grouped both lakes and taxa into categories best explained by their pH-related characteristics. Analysis of surficial sediment from lakes with known limnological characteristics is a useful approach for the study of the ecology and taxonomy of the Mallomonadaceae. Our data demonstrate that mallomonadacean distributions reflect lake conditions and, therefore, are potentially useful indicators in limnological and paleolimnological studies.
Ectomycorrhizal associations in jack pine stands in northeastern Alberta
Authors: Danielson R. M
Published: August 2008

Ectomycorrhizae of jack pine occurring in mature stands, on bare roadsides, and in a recently burned area were compared. Fifty-six fungus associates were identified from sporocarp collections. Species of Elaphomyces, Suillus, Cortinarius, Cantharellus, and hydnums were almost exclusively limited to mature stands. Laccaria proxima, Rhizopogon rubescens. Scleroderma macrorhizon, and Astraeus hygrometricus were typically found on disturbed sites. Visual observations and direct isolations from ectomycorrhizae further indicated that the symbionts differed between the burn site and mature jack pine – lichen woodlands. A majority of the ectomycorrhizae in all sites were nondescript and could not be identified by culturing. Unlike the vascular plants, ectomycorrhizal symbionts were very numerous without any single species or small group of species dominating jack pine root systems. Pure culture syntheses confirmed that Tricholoma flavovirens, T. pessundatum, T. zelleri, Suillus flavovirens, S. albidipes, Cenococcum geophilum, Laccaria proxima. Scleroderma macrorhizon, Astraeus hygrometricus, Lactarius paradoxus, Coltrichia perennis, and Bankera fuligineo-alba were ectomycorrhizal associates of jack pine.
Age and temperature effects on saturation of leaf fatty acids of Saxifraga cernua, an arctic herb
Authors: Marie Beverley A. H. , Cummins W. Raymond
Published: August 2008

Leaves from 90-day-old Saxifraga cernua plants which had been grown at 10 °C had more linolenic acid and less linoleic, oleic, and palmitic acids than did leaves from plants grown at 20 °C. When the linolenic acid content of the leaves was measured over the entire life cycle, the plants reached 66 days of age before the linolenic acid content was greater in 10 °C-grown plants than in 20 °C-grown plants. Plants grown at 20 °C, which had been shifted to 10 °C for 4 days, generally had more linolenic acid than plants grown continually at 20 °C, but there were few statistically significant differences. Larger increases tended to occur in plants which were older than 58 days at the time of the temperature shift. The corresponding shift of 10 °C-grown plants to 20 °C for 4 days resulted in inconsistent differences in linolenic acid content.
Natural uranium concentrations of native plants over a low-grade ore body
Authors: Sheppard Marsha I. , Thibault D. H.
Published: August 2008

Plant uranium concentrations generally reflect soil or rock substrate concentrations in upland areas, but they may not in lowland areas where the rhizoids of Sphagnum spp. and the rocks of Ledum groenlandicum may be in direct contact either continuously or on a seasonal basis with the groundwater. This study points out the importance of selecting plant species and collection sites where the true substrate can be well defined and sampled. Sphagnum spp. and Ledum groenlandicum best reflect the substrate uranium concentrations in lowland areas, Umbilicaria spp. and Cladonia spp. in rock outcrop, and Picea mariana and Betula papyrifera in upland locations. The study shows the best plant part to sample is the older tissue such as the stems, twigs, and wood. Since no systematic changes in plant tissue concentrations were found throughout the season, sampling can be carried out anytime. Expression of soil concentrations on an ash weight basis gave a considerably different result than those on a dry weight basis, particularly when comparisons were made between litter-enriched mineral soil and true organic soils. The amount of ash varied among plant organs, species, and taxonomic divisions, and a constant value cannot be used to convert plant ash concentrations to concentrations on a dry weight basis.
Effects on Rainbow Trout (Salmo gairdneri) of a Chronic Exposure to Waterborne Selenium
Authors: Hodson P. V. , Spry D. J. , Blunt B. R.
Published: August 2008

The 96-h and 9-d LC50s of selenium for rainbow trout (Salmo gairdneri) averaged 8.1 and 6.5 mg∙L−1, respectively. A sublethal exposure of rainbow trout from the newly fertilized egg stage until 44 wk posthatch to 4.4–53 μg∙L−1 of waterborne selenium resulted in a variety of subtle responses. Significantly increased mortality of eyed eggs was observed at selenium concentrations greater than or equal to 28 μg∙L−1 and decreased red blood cell volumes and cellular blood iron at concentrations greater than or equal to 53 and 16 μg∙L−1, respectively. Although the highest eyed egg mortality at 47 μg∙L−1 selenium was double that of control, total mortality was only 6.5%. Similarly, the blood parameters decreased from control levels by a maximum of 30% and the fish appeared to be compensating for these changes by increased erythropoiesis. Overall, the fish responded to selenium exposure at concentrations between 100 and 250 times the normal background concentrations in surface waters but the level of response was low. Analyses of tissue selenium at 44 wk posthatch indicated that residues clearly reflected exposure, that liver, digestive tract, and kidney accumulated the highest residues, that selenium tissue concentrations may be regulated, and that specific tissues provide a better basis for monitoring selenium exposure than whole body analyses.Key words: selenium, toxicity, fish, chronic, rainbow trout
Distribution of Commercial Troll Fishing Vessels off Southwest Vancouver Island in Relation to Fishing Success and Oceanic Water Properties and Circulation
Authors: Healey Michael C. , Thomson Richard E. , Morris John F. T.
Published: August 2008

During April to September 1982 and 1983 we recorded detailed distribution patterns of salmon troll fishing vessels off southwestern Vancouver Island by means of a Coast Guard navigational radar at Ucluelet, British Columbia. The vessels adopted characteristic seasonal distributions along the coast that were related to capture success in the fishery. Vessel aggregations were related to persistent features of water property structure and circulation on the continental shelf. In particular, dense concentrations of fishing vessels occurred where there was locally intensified upwelling associated with: (1) topographically induced rectification of tidal flow at the margins of shallow fishing banks; (2) a mesoscale, quasi-permanent, cyclonic eddy off Juan de Fuca Strait; and (3) the transition zone between the poleward flowing Vancouver Island Coastal Current and the equatorward flowing shelf-break current. In our view, the fishing vessel distributions reflect salmon distributions. Therefore, the association between vessel aggregations and local upwelling illustrates a response of the salmon to local features of their physical environment. This response is probably mediated through the food supply, with food organisms aggregating in the vicinity of local upwelling and salmon aggregating in the patches of food.
Horizontal and Vertical Movements of Adult Steelhead Trout, Oncorhynchus mykiss, in the Dean and Fisher Channels, British Columbia
Authors: Ruggerone Gregory T. , Quinn Thomas P. , McGregor Ian A. , Wilkinson Thomas D.
Published: August 2008

Horizontal and vertical movements of adults steelhead trout, Oncorhynchus mykiss, in the Dean and Fisher channels, British Columbia, were examined using radio and ultrasonic telemetry. Nineteen steelhead, captured by purse seine in 1987 and fitted with radio tags, averaged 17.2 ± 2.2 (SE) km/d to travel 96.4 km from the capture/release site to the Dean River mouth. Detailed movement patterns were assessed from six steelhead tracked for 224 h (21.0–49.8 h/fish) using ultrasonic tags in 1988. Gross and net travel rates of steelhead averaged 2.0 and 0.8 km/h, respectively, indicating considerable milling by the fish. Gross movement during daylight [Formula: see text] was twice that during the night [Formula: see text] and most movement at night was attributed to tidal currents. The steelhead swam primarily on the surface throughout the fjord, regardless of salinity and temperature stratification. Geometric mean depth was 1.6 m and the fish spent, on average, 72% of the time in the top 1 m (the warmest and least saline water available). Median time between dives to 5 m (near the halocline) was 9 min, although 14% of the surface intervals exceeded 1 h. These results are discussed in relation to several hypotheses regarding guidance mechanisms used by migrating fishes.
Effects of Nutritional Regime on Correlates of Growth Rate in Juvenile Atlantic Cod (Gadus morhua): Comparison of Morphological and Biochemical Measurements
Authors: Foster A. R. , Houlihan D. F. , Hall S. I.
Published: August 2008

The effects of both long-term (35 d of daily feeding, feeding every second day, or starvation) and short-term (up to 15 d of refeeding following starvation) nutritional regimes on morphological (tissue-somatic indices) and biochemical measurements (RNA concentration, RNA/protein ratio, RNA/DNA ratio, and cytochrome c oxidase activity (CCO)) were investigated for a variety of Atlantic cod (Gadus morhua) tissues. Liver-somatic index was the morphological index most sensitive to both the long- and short-term nutritional regimes. The majority of the tissue RNA measurements demonstrated positive linear relationships with growth rate, although stomach, intestine, and white muscle were the most sensitive tissues for all the treatments. Most of the tissues examined also showed positive linear relationships with growth rate, although stomach, intestine, and white muscle were the most sensitive tissues for all the treatments. Most of the tissues examined also showed positive linear relationships between CCO specific activity and long-term growth rate. However, tissue CCO specific activity was relatively insensitive to the short-term alterations in nutritional regime.
Components Analysis of a Density-Dependent Catchability Coefficient in a Salmon Hook and Line Fishery
Authors: Shardlow Thomas F.
Published: August 2008

The relationship between the catch per unit of effort (C/E) of salmon anglers and salmon abundance was determined by using simultaneous estimates of both C/E and salmon density (n). Salmon in their natural marine environment were observed as they approached fishing gear. The components of catch, such as the number of fish approaching, attacking, and biting the lure per unit of fishing effort, were recorded. C/E was not linearly related to density because the estimate of the catchability coefficient q increased with abundance. This result contrasts with previous empirical studies of catchability in which q declined with fish abundance. However, because only historical catch records had been used to estimate catchability, the interactions between the fishing gear and fish were not available in past research. This study suggests that feeding facilitation among salmon may be the mechanism underlying increased catchability with abundance.
Reproductive Biology of Atlantic Halibut (Hippoglossus hippoglossus) in Canadian Waters
Authors: Neilson John D. , Kearney John F. , Perley Peter , Sampson Harry
Published: August 2008

Through examination of commercial fishery samples, surveys conducted from research vessels, and fishery observer programs, the reproductive biology of Atlantic halibut (Hippoglossus hippoglossus) in the Canadian North Atlantic is described. Using data derived from conventional techniques including histology and visual assessment of maturity, and a more novel approach using image analyses equipment, halibut were found to be group-synchronous spawners whose spawning activity peaks in the November–December period, considerably earlier than was previously thought. Our analyses also allowed us to comment on the life history of Atlantic halibut in Canadian waters. The comparative absence of spawners in the continental shelf/slope areas may mean that halibut spawn in comparatively deep water, consistent with the habits of the Pacific member of the genus, H. stenolepis. Immature fish typically occurred on the southwestern Scotian Shelf but rarely off Newfoundland, supporting the view that the former area is an important rearing area for immature halibut.