bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of the feasibility of relative 3D dosimetry in the Radiologic Physics Center Head and Neck IMRT phantom using Presage/optical‐CT
Authors: Sakhalkar Harshad , Sterling David , Adamovics John , Ibbott Geoffrey , Oldham Mark
Published: June 2009

This study presents the application of the Presage/optical‐CT 3D dosimetry system for relative dosimetry in the Radiologic Physics Center (RPC) Head and Neck (H&N) IMRT phantom. Performance of the system was evaluated by comparison with the “gold‐standard” RPC credentialing test. A modified Presage cylindrical insert was created that extended the capability of the RPC H&N phantom to 3D dosimetry. The RPC phantom was taken through the entire treatment planning procedure with both the standard RPC insert and the modified Presage insert. An IMRT plan was created to match the desired dose constraints of the credentialing test. This plan was delivered twice to the RPC phantom: first containing the standard insert, and then again containing the Presage insert. After irradiation, the standard insert was sent for routine credentialing analysis; including point dose measurements (TLD) and planar Gafchromic® EBT film measurement. The 3D dose distribution from Presage was read out at Duke using the OCTOPUS™ 5X optical‐CT scanner. The Presage distribution was compared with gold‐standard EBT measurement (determined by the RPC) and the calculated Eclipse distribution. The agreement between the normalized EBT, Presage, and Eclipse distributions, in the central axial plane was evaluated using profiles and gamma‐map comparisons (4% dose difference and distance to agreement). Profiles showed good agreement between EBT, Presage, and Eclipse distributions. 2D gamma‐map comparisons between all three modalities showed at least 98% pass rate. The excellent agreement between Presage and EBT in the central plane established Presage as a standard against which to evaluate the accuracy of the 3D calculated Eclipse distribution. A gamma comparison between normalized Presage and Eclipse 3D distributions gave an overall pass rate of . In conclusion, the Presage/optical‐CT system was found to be feasible for relative 3D dosimetry in the RPC IMRT H&N phantom. The potential to extend the RPC IMRT credentialing procedure to 3D may be feasible provided accurate calibration to dose (Gy) and robustness to shipping stress are demonstrated.
Optimal “image‐based” weighting for energy‐resolved CT
Authors: Schmidt Taly Gilat
Published: June 2009

This paper investigates a method of reconstructing images from energy‐resolved CT data with negligible beam‐hardening artifacts and improved contrast‐to‐nosie ratio (CNR) compared to conventional energy‐weighting methods. Conceptually, the investigated method first reconstructs separate images from each energy bin. The final image is a linear combination of the energy‐bin images, with the weights chosen to maximize the CNR in the final image. The optimal weight of a particular energy‐bin image is derived to be proportional to the contrast‐to‐noise‐variance ratio in that image. The investigated weighting method is referred to as “image‐based” weighting, although, as will be described, the weights can be calculated and the energy‐bin data combined prior to reconstruction. The performance of optimal image‐based energy weighting with respect to CNR and beam‐hardening artifacts was investigated through simulations and compared to that of energy integrating, photon counting, and previously studied optimal “projection‐based” energy weighting. Two acquisitions were simulated: dedicated breast CT and a conventional thorax scan. The energy‐resolving detector was simulated with five energy bins. Four methods of estimating the optimal weights were investigated, including task‐specific and task‐independent methods and methods that require a single reconstruction versus multiple reconstructions. Results demonstrated that optimal image‐based weighting improved the CNR compared to energy‐integrating weighting by factors of 1.15–1.6 depending on the task. Compared to photon‐counting weighting, the CNR improvement ranged from 1.0 to 1.3. The CNR improvement factors were comparable to those of projection‐based optimal energy weighting. The beam‐hardening cupping artifact increased from 5.2% for energy‐integrating weighting to 12.8% for optimal projection‐based weighting, while optimal image‐based weighting reduced the cupping to 0.6%. Overall, optimal image‐based energy weighting provides images with negligible beam‐hardening artifacts and improved CNR compared to energy‐integrating and photon‐counting methods.
Cone‐beam CT image reconstruction with extended range
Authors: Grimmer Rainer , Oelhafen Markus , Elstrøm Ulrik , Kachelrieß Marc
Published: June 2009

In circular cone‐beam CT the Feldkamp [Feldkamp–Davis–Kress (FDK)] algorithm is the most prominent image reconstruction algorithm. For example, in radiation oncology images reconstructed with the Feldkamp algorithm are used for accurate patient positioning. The scan and reconstruction volumes are limited by the size of the flat panel detector. Flat panel detectors, however, are expensive and difficult to manufacture in large size. For numerous treatment techniques, extending this scan volume would be very beneficial. In most applications, data from 360° or more are available. However, usually only those slices are reconstructed where each pixel is seen under the full 360° range. Yet for a 360° scan there are regions that are seen by less than 360°, namely, those that lie further off the plane of the circular source trajectory. Performing a reconstruction also for those slices where all voxels are seen at least by 180° will extend the range and therefore increase the dose usage. In this work a new method is presented that reconstructs also those slices where some or all pixels receive less than 360° but at least 180° of the data. The procedure significantly increases the longitudinal range of the reconstructed volume. As opposed to the existing techniques, the proposed method does not necessitate any multiple convolutions or multiple backprojections, lending itself therefore for a very efficient implementation. To validate the abilities of the extended reconstruction, the authors performed an evaluation of the image quality by using simulated and measured CT data. The method shows good image quality on simulated phantom data as well as on clinical patient scans. Image noise and spatial resolution behave as expected. This means that the noise equals FDK values in the normal region and increases in the extended region due to reduced data redundancies. The extended Feldkamp demonstrates its ability to extend the reconstructable range and appears to be useful in clinical practice.
Dosimetric properties of an amorphous‐silicon EPID used in continuous acquisition mode for application to dynamic and arc IMRT
Authors: McCurdy B. M. C. , Greer P. B.
Published: June 2009

Dosimetric properties of an amorphous‐silicon electronic portal imaging device (EPID) operated in a real‐time acquisition mode were investigated. This mode will be essential for time‐resolved dose verification of dynamic (sliding window) intensity modulated radiation therapy (IMRT) and intensity modulated arc radiation therapy (arc‐IMRT). The EPID was used in continuous acquisition mode (i.e., “cine” mode) where individual sequential image frames are acquired in real time. The properties studied include dose linearity, reproducibility of response, and image stability. Results of using the continuous acquisition mode with several example treatments including dynamic IMRT, arc treatment, and single‐arc‐IMRT are compared to results using the well‐studied integrated acquisition mode (i.e., “frame averaging” or “IMRT” mode). Real‐time EPID response was also compared to real‐time ion‐chamber data for selected points in the deliveries. The example treatment deliveries in both continuous and integrated acquisition modes were converted to arbitrary EPID dose units via a calibration field. The summation of all acquired continuous mode images was compared using percentage dose difference to the single image acquired in the integrated mode using in‐field pixels only (defined as those pixels of maximum, in‐field signal). Using the continuous acquisition mode, the EPID response was not linear with dose. It was found that the continuous mode dose response corresponded approximately to dropping one image per acquisition session. Reproducibility of EPID response to low monitor units (MUs) was found to be poor but greatly improved with increasing MU. Open field profiles were found to be stable in the cross‐plane direction but required several frames to become stable in the in‐plane direction. However, both of these issues are clinically insignificant due to arc‐IMRT deliveries requiring relatively large monitor units . Analysis of the five IMRT, arc, and arc‐IMRT tests revealed that all examples compared to within 2% of maximum dose for more than 95% of in‐field pixels. The continuous acquisition mode is suited to time‐resolved dosimetry applications including arc‐IMRT and dynamic IMRT, giving comparable dose results to the well‐studied integrated acquisition mode, although caution should be used in low MU applications. Time‐resolved EPID dose information also compared well to time‐resolved ion‐chamber measurements.
Dosimetric comparison of four new design brachytherapy sources: Optimal design using silver and copper rod cores
Authors: Hosseini S. Hamed , Sadeghi Mahdi , Ataeinia Vahideh
Published: June 2009

Four new brachytherapy sources, IRA1‐, IRA2‐, IRA3‐, and IRA4‐, have been developed at Agricultural, Medical, and Industrial Research School and are designed for permanent implant application. With the goal of determining an optimal design for a source, this article compares the dosimetric properties of these sources with reference to the authors’ earlier IRA‐ source. The four new sources differ in end cap configuration and thickness and in the core material, silver or copper, that carries the adsorbed . Dosimetric data derived from the authors’ Monte Carlo simulation results are reported in accordance with the updated AAPM Task Group No. 43 report (TG‐43U1). For each source, the authors obtained detailed results for the dose rate constant , the radial dose function , the anisotropy function , and the anisotropy factor . In this study, the optimal source IRA3‐ provides the most isotropic dose distribution in water with the dose rate constant of . The IRA3‐ design has a silver rod core combined with thin‐wall, concave end caps. Finally, the authors compared the results for their optimal source with published results for those of other source manufacturers.
Monte Carlo calculations of correction factors for plastic phantoms in clinical photon and electron beam dosimetry
Authors: Araki Fujio , Hanyu Yuji , Fukuoka Miyoko , Matsumoto Kenji , Okumura Masahiko , Oguchi Hiroshi
Published: June 2009

The purpose of this study is to calculate correction factors for plastic water (PW) and plastic water diagnostic‐therapy (PWDT) phantoms in clinical photon and electron beam dosimetry using the EGSnrc Monte Carlo code system. A water‐to‐plastic ionization conversion factor for PW and PWDT was computed for several commonly used Farmer‐type ionization chambers with different wall materials in the range of 4–18 MV photon beams. For electron beams, a depth‐scaling factor and a chamber‐dependent fluence correction factor for both phantoms were also calculated in combination with NACP‐02 and Roos plane‐parallel ionization chambers in the range of 4–18 MeV. The values for the plane‐parallel chambers were evaluated from the electron fluence correction factor and wall correction factors and for a combination of water or plastic materials. The calculated and values were verified by comparison with the measured values. A set of values computed for the Farmer‐type chambers was equal to unity within 0.5% for PW and PWDT in photon beams. The values also agreed within their combined uncertainty with the measured data. For electron beams, the values computed for PW and PWDT were from 0.998 to 1.000 and from 0.992 to 0.997, respectively, in the range of 4–18 MeV. The values for PW and PWDT were from 0.998 to 1.001 and from 1.004 to 1.001, respectively, at a reference depth in the range of 4–18 MeV. The difference in between water and plastic materials for the plane‐parallel chambers was 0.8% at a maximum. Finally, values evaluated for plastic materials were equal to unity within 0.6% for NACP‐02 and Roos chambers. The values also agreed within their combined uncertainty with the measured data. The absorbed dose to water from ionization chamber measurements in PW and PWDT plastic materials corresponds to that in water within 1%. Both phantoms can thus be used as a substitute for water for photon and electron dosimetry.
STEP: Spatiotemporal enhancement pattern for MR‐based breast tumor diagnosis
Authors: Zheng Yuanjie , Englander Sarah , Baloch Sajjad , Zacharaki Evangelia I. , Fan Yong , Schnall Mitchell D. , Shen Dinggang
Published: June 2009

The authors propose a spatiotemporal enhancement pattern (STEP) for comprehensive characterization of breast tumors in contrast‐enhanced MR images. By viewing serial contrast‐enhanced MR images as a single spatiotemporal image, they formulate the STEP as a combination of (1) dynamic enhancement and architectural features of a tumor, and (2) the spatial variations of pixelwise temporal enhancements. Although the latter has been widely used by radiologists for diagnostic purposes, it has rarely been employed for computer‐aided diagnosis. This article presents two major contributions. First, the STEP features are introduced to capture temporal enhancement and its spatial variations. This is essentially carried out through the Fourier transformation and pharmacokinetic modeling of various temporal enhancement features, followed by the calculation of moment invariants and Gabor texture features. Second, for effectively extracting the STEP features from tumors, we develop a graph‐cut based segmentation algorithm that aims at refining coarse manual segmentations of tumors. The STEP features are assessed through their diagnostic performance for differentiating between benign and malignant tumors using a linear classifier (along with a simple ranking‐based feature selection) in a leave‐one‐out cross‐validation setting. The experimental results for the proposed features exhibit superior performance, when compared to the existing approaches, with the area under the ROC curve approaching 0.97.
An analytical approach to estimating the first order scatter in heterogeneous medium. II. A practical application
Authors: Yao Weiguang , Leszczynski Konrad W.
Published: June 2009

Recently, the authors proposed an analytical scheme to estimate the first order x‐ray scatter by approximating the Klein‐Nishina formula so that the first order scatter fluence is expressed as a function of the primary photon fluence on the detector. In this work, the authors apply the scheme to experimentally obtained 6 MV cone beam CT projections in which the primary photon fluence is the unknown of interest. With the assumption that the higher‐order scatter fluence is either constant or proportional to the first order scatter fluence, an iterative approach is proposed to estimate both primary and scatter fluences from projections by utilizing their relationship. The iterative approach is evaluated by comparisons with experimentally measured scatter‐primary ratios of a Catphan phantom and with Monte Carlo simulations of virtual phantoms. The convergence of the iterations is fast and the accuracy of scatter correction is high. For a sufficiently long cylindrical water phantom with 10 cm of radius, the relative error of estimated primary photon fluence was within ±2% and ±4% when the phantom was projected with 6 MV and 120 kVp x‐ray imaging systems, respectively. In addition, the iterative approach for scatter estimation is applied to 6 MV x‐ray projections of a QUASAR and anthropomorphic phantoms (head and pelvis). The scatter correction is demonstrated to significantly improve the accuracy of the reconstructed linear attenuation coefficient and the contrast of the projections and reconstructed volumetric images generated with a linac 6 MV beam.
A practical way to improve contrast‐to‐noise ratio and quantitation for statistical‐based iterative reconstruction in whole‐body PET imaging
Authors: Fin Loïc , Bailly Pascal , Daouk Joël , Meyer Marc‐Etienne
Published: June 2009

In whole‐body positron emission tomography (PET) imaging, the detection of small uptake foci (i.e., around two or three times the tomograph's spatial resolution) is a critical issue. Indeed, spatial resolution is altered by postreconstruction smoothing operations used to reduce the noise introduced by (among other things) an inaccurate system matrix. The authors previously proposed a device‐dedicated projector, easily applicable on a clinical gantry, based on point‐source measurements, which introduces less noise than a geometrical model. In the present study, they took advantage of the lower noise levels by reducing the postfilter and then quantified the approach's impact on image quality. This study was performed on an IEC Body Phantom Set™ filled with (sphere‐to‐background activity ratio: 4:1). The same acquisition was reconstructed with either (i) a clinical system based on a geometrical tomographic operator (OSEM̱CL) or (ii) an OSEM algorithm using the suggested system matrix (OSEM̱DR). In order to compare the resulting images, they set the 3D Gaussian postfilter (3DGPF) for OSEM̱DR so as to obtain similar background signal‐to‐noise ratio (SNR) to that of OSEM̱CL with a Gaussian postfilter full width at half maximum of (as recommended for whole‐body imaging on a Biograph™6). They then assessed the contrast‐to‐noise ratio (CNR) and quantitation [contrast recovery (CR)] for the phantom's four smallest spheres (with internal diameters of 10, 13, 17, and ). Evaluation of 3DGPFs ranging from showed that a value of in OSEM̱DR gave the closest background SNR to that of OSEM̱CL with a 3DGPF of . For all studied targets, the CNR was higher with OSEM̱DR than with OSEM̱CL. For the 10 and spheres, OSEM̱DR increased the size of the CNR peaks by 37% and 20%, relative to OSEM̱CL. The OSEM̱DR technique yielded higher CR values than OSEM̱CL did. For the 10, 13, 17, and spheres, the CR values at eight iterations were 0.5, 0.6, 1.1, and 1.0 for OSEM̱DR and 0.3, 0.4, 0.9, and 0.8 for OSEM̱CL. They evaluated a practical method for determining a device‐dedicated system matrix based on point‐source acquisitions. This tomographic operator is more realistic than geometrical system matrix and introduces less noise into PET images during statistical reconstruction; it thus reduces the extent of postfiltering operations required. Thus, spatial resolution is better maintained with OSEM̱DR than with clinical reconstruction. They showed that this method improves the contrast‐to‐noise ratio and quantification of uptake foci (especially those that are at the system's limit of detection) and, in a clinical context, could allow better detection and earlier diagnosis.
Measuring the Cosmic-Ray Acceleration Efficiency of a Supernova Remnant
Authors: Helder E. A. , Vink J. , Bassa C. G. , Bamba A. , Bleeker J. A. M. , Funk S. , Ghavamian P. , van der Heyden K. J. , Verbunt F. , Yamazaki R.
Published: June 2009

Cosmic Shock Waves

Cosmic rays are high-energy charged particles that bombard Earth from all directions in the sky; those originating from within our Galaxy are thought to be accelerated in the shockwaves produced by supernova explosions.

Helder
et al.

(p.
719
, published online 25 June; see the Perspective by

Raymond

) measured the velocity of a section of the blast wave created by supernova RCW 86, an exploding star believed to have been witnessed by Chinese astronomers in 185 A.D., and the post-shock proton temperature. The post-shock proton temperature was much lower than would be expected without any cosmic ray acceleration, which implies that the pressure induced by cosmic ray exceeds the thermal pressure behind the shock.
A Gene Network Regulating Lysosomal Biogenesis and Function
Authors: Sardiello Marco , Palmieri Michela , di Ronza Alberto , Medina Diego Luis , Valenza Marta , Gennarino Vincenzo Alessandro , Di Malta Chiara , Donaudy Francesca , Embrione Valerio , Polishchuk Roman S. , Banfi Sandro , Parenti Giancarlo , Cattaneo Elena , Ballabio Andrea
Published: June 2009

Master Controller

Cellular organelles allow the localized regulation of specialized processes. Under certain conditions, such as increased growth, organelles may be required to alter their function. Coordinated regulation of the gene networks required for mitochondrial and endoplasmic reticulum function has been observed. Now,

Sardiello
et al.

(p.
473
; published online 25 June) have discovered a gene network regulating the lysosome, the major organelle involved in the degradation of internalized macromolecules. Many lysosomal genes were regulated by a single transcription factor, TFEB. TFEB itself can be activated when the lysosome malfunctions and can regulate both the abundance of lysosomes found in the cell, as well as the ability to degrade complex molecules, including a mutant protein that accumulates in patients with Huntington's disease. These results may have implications for the treatment of human lysosomal storage disorders, which are characterized by the aberrant accumulation of macromolecules causing cellular dysfunction.
Soluble CD30 as a prognostic factor for outcome following renal transplantation
Authors: Platt R E , Wu K S T , Poole K , Newstead C G , Clark B
Published: June 2009

Aims:

To determine whether measurement of soluble CD30 (sCD30) levels predicts for early rejection in a cohort of first deceased kidney transplant recipients.

Methods:

Pre-transplant serum samples were analysed for sCD30 levels using a commercial ELISA kit (Biotest). A 100 U/ml cut-off for “high sCD30” was applied. Clinical outcome parameters were biopsy-proven rejection episodes, creatinine levels and glomerular filtration rate.

Results:

In the cohort of patients who experienced at least one episode of rejection in the first 6 months post-transplant, levels of pre-transplant sCD30 were significantly higher than in those who did not experience rejection. Despite this association, the occurrence of a high sCD30 level did not predict for rejection on an individual basis.

Conclusions:

The prognostic value of pre-transplant sCD30 testing is diminished by the large number of patients with high sCD30 levels who do not develop rejection. Although this limits the utility of the test in informing clinical management of individual patients, a high pre-transplant sCD30 level should still be considered a risk factor for poorer outcome.
Malignant myoepithelioma arising in adenomyoepithelioma of the breast and coincident multiple gastrointestinal stromal tumours in a patient with neurofibromatosis type 1
Authors: Hegyi L , Thway K , Newton R , Osin P , Nerurkar A , Hayes A J , Fisher C
Published: June 2009

A 41-year-old female patient with neurofibromatosis type 1 (NF-1) presented with a breast lump and anaemia related to gastrointestinal bleeding. She was found to have malignant myoepithelioma of the breast and simultaneously multiple gastrointestinal stromal tumours (GISTs) of the small bowel. Molecular studies showed a silent germline mutation in exon 9 of theKITgene of both tumours. The common gene mutations characteristic of sporadic GISTs were not identified in these tumours, consistent with the literature, suggesting that gene mutations in GISTs are either absent or late events in patients with NF-1.
An unusual case of Epstein–Barr virus driven lymphoproliferative disorder of the conjunctiva which mimicked a high grade lymphoma: a sheep in wolf’s clothing
Authors: Powari M , Simpson A , Quinn A , McCullagh P , Sarsfield P
Published: June 2009

Lymphoid proliferations represent 25–33% of acquired sub-epithelial conjunctival lesions which are excised or biopsied in patients over 15 years of age. These lesions are reported in association with Epstein–Barr virus (EBV). One such case of EBV associated spontaneously regressed monoclonal B cell infiltrate in conjunctiva that mimicked a large B cell lymphoma is reported.
V600EBRAFmutations are alternative early molecular events in a subset ofKIT/PDGFRAwild-type gastrointestinal stromal tumours
Authors: Agaimy A , Terracciano L M , Dirnhofer S , Tornillo L , Foerster A , Hartmann A , Bihl M P
Published: June 2009

Background:

A small subset (10–15%) of gastrointestinal stromal tumours (GISTs) lack mutations inKITandPDGFRA(wild-type GIST). Recently, a novelBRAFexon 15 mutation (V600E) was detected in imatinib-naive wild-type high-risk intestinal GISTs (4%). However, the frequency and distribution ofBRAFmutations within the spectrum of GISTs, and whether they might represent secondary events acquired during tumour progression, remain unknown.

Methods:

69 GISTs (39KITmutants, 2PDGFRAmutants and 28 wild-type) were analysed for mutations inBRAFexon 15 andKRASexon 2. To assess the stage at which these mutations might occur in GIST, a considerable number of incidental gastric (n = 23) and intestinal (n = 2) tumours were included.

Results:

BRAFmutations (V600E) were detected in 2 of 28 wild-type GISTs (7%), but in none of the 41KIT/PDGFRAmutants. NoKRASmutation was detected. The twoBRAF-mutated GISTs measured 4 mm in diameter and originated in the gastric body and the jejunum in two men (mean age, 76 years). Both tumours were mitotically inactive KIT-positive spindle-cell GISTs that were indistinguishable histologically from their more commonKIT-mutated counterparts.

Conclusion:

BRAFmutations represent an alternative molecular pathway in the early tumorigenesis of a subset ofKIT/PDGFRAwild-type GISTs and are per se not associated with a high risk of malignancy. Mutations inKIT,PDGFRAandBRAFwere mutually exclusive in this study. Results from this and a previous study indicate thatBRAF-mutated GISTs show a predilection for the small bowel (four of five tumours), but this needs further evaluation in larger studies.
Quality of teaching in chemical pathology: ability of interns to order and interpret laboratory tests
Authors: Stanfliet J C , Macauley J , Pillay T S
Published: June 2009

Background and objective:

There has been a steady decline in the overt teaching of many basic and pathology sciences in the medical curriculum worldwide. As interns are the doctors most likely to request and act on tests, an assessment of their confidence in dealing with laboratory investigations was undertaken.

Methods:

Interns at two hospitals in Cape Town, South Africa, were asked to complete a structured questionnaire designed to assess their confidence in ordering and interpreting a number of tests. The questionnaire also probed their desire for further teaching and the preferred delivery vehicle for such teaching.

Results and conclusions:

61 out of 117 questionnaires were returned. Interns were confident in the use of common tests, but 23% were not confident in interpreting a test that they were confident in ordering. All respondents felt they would benefit from teaching in at least one area and lectures were the preferred method, although the majority felt it very likely that they would complete an online tutorial if available. The results suggest that institutions need to devise strategies to fulfil the learning needs of new graduates in the area of chemical pathology and clinical biochemistry.
Cytological features of melanoma in exfoliative fluid specimens
Authors: Murali R , Loughman N T , McKenzie P R , Watson G F , Thompson J F , Scolyer R A
Published: June 2009

Aims:

To describe the cytological appearances of melanoma in fluid specimens and potential diagnostic pitfalls in interpreting such specimens, which have been infrequently reported in the literature.

Methods:

Cases of melanoma diagnosed at a single institution between 1993 and 2008 in cytology specimens of fluids (pleural, ascitic, cerebrospinal and other fluids), but excluding fine needle biopsy specimens, were identified and reviewed.

Results:

32 fluid specimens containing metastatic melanoma (from 26 patients) were identified. Most of the specimens were moderately cellular and showed moderate to marked nuclear pleomorphism. Mitotic figures and intranuclear cytoplasmic invaginations were identified in 11 (34.4%) and seven (21.9%) cases, respectively. Melanin pigment was seen in eight (25.0%) cases. Variable numbers of histiocytes were present, and mesothelial cells were present in body cavity fluid specimens.

Conclusions:

In fluid specimens, reactive mesothelial cells and histiocytes may mimic epithelioid melanoma cells. Awareness of the morphological features and diagnostic pitfalls of melanoma in fluids is necessary to avoid the potentially serious consequences of misdiagnosis.
Dynamic simulation of falling weight deflectometer tests on flexible pavements using the spectral element method: forward calculations
Authors: Grenier Simon , Konrad Jean-Marie , LeBœuf Denis
Published: June 2009

A dynamic analysis based on the spectral element method is described for the interpretation of falling weight deflectometer (FWD) tests on flexible pavements. This dynamic approach was implemented in the computer code Dynamic Analysis of Pavement - Université Laval (DYNAPAV-UL) that includes both frequency-independent hysteretic damping and frequency-dependent viscous damping material models. A parametric study was conducted on a four-layer flexible pavement to evaluate the influence of different layer moduli on deflection basins and deflection histories. The viscous behaviour of the asphalt concrete layer was also investigated. While the deflection basin currently used in static methods gives some details of the pavement response under transient loading, the simulations of FWD tests using the dynamic model suggest that the time histories should be included as well for the interpretation of FWD deflection measurements. In fact, important dynamic phenomena due to inertial effects and viscous effects are only revealed by deflection histories.
Dynamic interpretation of falling weight deflectometer tests on flexible pavements using the spectral element method: backcalculation
Authors: Grenier Simon , Konrad Jean-Marie
Published: June 2009

A robust backcalculation methodology that uses the Levenberg–Marquardt iterative minimization technique is presented to identify the value of unknown layer parameters from falling weight deflectometer (FWD) tests using a dynamic approach based on the spectral element method. Backcalculation is performed in the time-domain with 20 observations on each deflection history. The efficiency of the proposed methodology is demonstrated by interpreting FWD tests on three flexible pavements that cover a variety of structures, soil, and bedrock conditions. Results indicate that the dynamic approach is capable of simulating quite well the measured deflection histories using effective backcalculated moduli. In addition, comparison of critical strains between static and dynamic interpretation of FWD tests indicates that both approaches predict similar traction strains at the bottom of the asphalt concrete layer. However, the prediction of the compression strain in the subgrade with the static approach is erratic compared with the dynamic method.
Characterization of 1-h rainfall temporal patterns using a Kohonen neural network: a Québec City case study
Authors: Pelletier Geneviève , Anctil François , Filion Mélanie
Published: June 2009

After only a few years of operation, an extensive rain gauge network provides fruitful information on temporal patterns of local storms, helping urban water, managers with in the difficult choice of appropriate design storms. A total of 1470 1-h storms were identified for the period 1999–2005 in Québec City based on rainfall depth and interevent time criteria. Taking advantage of a clustering technique, the Kohonen neural network, 1-h storms were divided into 16 clusters depending on similarities in their temporal patterns, and then lumped into four groups. The database revealed that about one-third of all storms have a uniform intensity, one-third are early-peaking, and one-third are either symmetrical or late-peaking. Early-peaking patterns include the highest maximal 5-min intensity: 0.22–0.30 of the rainfall depth range, therefore in the same range as common Canadian 10-year design storms.
Toward a better understanding of the dynamic characteristics of single-storey braced steel frame buildings in Canada
Authors: Lamarche Charles-Philippe , Proulx Jean , Paultre Patrick , Turek Martin , Ventura Carlos E. , Le Thien Phu , Lévesque Cédrik
Published: June 2009

Single-storey braced steel frame buildings (SSBSFs) are currently the most widely used commercial structures, which include strip malls, power centres, warehouses, small and medium-sized industrial plants. The lateral seismic or wind forces acting on such low-rise structures are usually transferred from a metal roof-deck diaphragm to a system of vertical bracing members. Because these flexible roof diaphragms have a considerable effect on the dynamic response of SSBSFs during an earthquake, they also play an important role in the evaluation of the fundamental vibration period, a key parameter in determining the magnitude of the design seismic forces. It is therefore of utmost importance to reliably predict the fundamental period of SSBSFs. This paper presents the results of a four-year field measurement research project on the dynamic behaviour of SSBSFs. The goal of the project was to create a reliable database for the dynamic characteristics of SSBSFs (periods, mode shapes, and damping) and to find a relationship between them and the geometric parameters (height and plan dimensions). The field tests are described, along with the selected buildings and experimental setup. The measured fundamental periods are then compared to the National building code of Canada (NBCC) empirical equations. A statistical analysis of the data, based on different regression models, yielded new proposed building geometric parameters to be used in simple equations for the prediction of the fundamental period of SSBSFs.
Prediction of afflux on undistorted scale bridge model
Authors: Atabay Serter , Seckin Galip
Published: June 2009

This paper presents the results and findings from several sets of experimental data on afflux around bridge waterways in overbank flow condition. The paper also investigates the accuracy, capability, and suitability of one-dimensional hydraulic river modelling software (HEC-RAS and ISIS) to model flow through bridge structure. To eliminate a scaling effect between the laboratory-scale experiments and model techniques, all experimental results were scaled up using an undistorted-scale model in which both the vertical and horizontal scale ratio was 100. A total of six methods of predicting afflux, the energy method, the momentum method, the water surface profile (WSPRO) method, Yarnell's method (in HEC-RAS), the U.S. Bureau of Public Roads (USBPR) method, and the arch bridge method (in ISIS) were compared with scaled up experimental results. The results for ISIS are significantly different from the measured data and the output from HEC-RAS. The energy method and the momentum method in HEC-RAS are the most accurate methods to compute the afflux around the bridge waterways.
Evaluating road pricing with an engineering perspective: aggregate and disaggregate analysis
Authors: Tezcan Hüseyin Onur
Published: June 2009

The aim of this paper is to present the basic premises of modelling road pricing with an engineering perspective at aggregate and disaggregate levels. An engineering perspective is different than economic perspective according to its analytical and deterministic approach. In this paper most of the economic notions are deliberately simplified, especially at the aggregate level, to obtain a simple, easy to understand, and easy to run model. The paper also includes facts about basic theories of road pricing and economic modelling. To demonstrate the modelling approaches presented in this paper, a simple numerical example is assessed. The results show that aggregate analysis provides understanding of the extent of the impacts whereas disaggregate analysis offers more detailed information. Furthermore, analysis at both levels has the potential to perform a combined modelling study as well.
Une approche pour l’analyse des faiblesses du secteur des déchets solides en Tunisie à partir des contraintes et de leurs effets induits et cumulatifs
Authors: Cherif Mohamed , Bouchard Michel André
Published: June 2009

En dépit des ressources financières généralement limitées dans les pays émergents, en plus du manque de ressources humaines qualifiées et devant la pression qu’exerce le secteur des déchets sur l’environnement et la qualité de la vie dans ces pays, il est indispensable d’établir un ordre de priorité pour les interventions des pouvoirs publics dans le secteur des déchets et de cibler en priorité le traitement des origines des problèmes, en analysant les faiblesses, matérialisées par les causes des déficits et les obstacles devant une amélioration rapide de la situation. À travers le recoupement des effets induits de ces deux contraintes (causes et obstacles) cas par cas, nous avons montré que leurs effets cumulatifs peuvent générer une amplification des nuisances et aggraver ainsi la situation. La pondération des effets induits permet de quantifier l’effet cumulatif (0, + ou ++), ce qui pourrait indiquer, en fonction des moyens disponibles, le degré de pertinence des mesures réparatrices à engager (A, B ou C). Il ressort de la discussion des combinaisons les plus nuisibles que l’évaluation des effets induits et cumulatifs indique, par le biais d’un raisonnement plausible, le genre de mesures réparatrices à engager. Dans cette étude nous avons essayé de montrer que cette méthode s’adapte bien à l’évaluation de la gestion des déchets dans les pays émergents et ne se limite pas à la simple pondération des apparences, à l’instar de certains logiciels de conception stratégique qu’on trouve sur le marché, mais procède en premier lieu au recoupement des contraintes pour la détermination de leurs effets induits et cumulatifs. La pondération vise les effets et n’est alors plus aléatoire, car elle dépend d’un raisonnement justifié à la fois à l’amont et à l’aval. L’application de cette méthodologie de réflexion sur le secteur de gestion des déchets solides de la Tunisie, comme exemple de pays émergents, a confirmé l’efficacité d’un tel raisonnement et a mené à des mesures de réparation fondées.
Utilisation des écailles de cacao comme support de biofiltration pour le traitement d’effluents de l’industrie agro-alimentaireArticles envoyés à la Revue du génie et de la science de l'environnement.
Authors: Turcotte Véronique , Blais Jean-François , Mercier Guy , Drogui Patrick
Published: June 2009

L’industrie agro-alimentaire produit une quantité importante de résidus, ou co-produits, dont certains sont potentiellement valorisables. Dans cette étude, les écailles de cacao, un résidu de la fabrication du chocolat, ont été étudiées comme support de biomasse dans un biofiltre aérobie à co-courant ascendant. L’influence de divers paramètres (temps de rétention hydraulique (TRH), granulométrie du support, apport de nutriments, pH) a été vérifiée sur la performance d’élimination de la demande chimique (DCO) et biochimique (DBO5) en oxygène. Un support plastique (Kaldnes, K1) a été utilisé comme support contrôle de biomasse. Les écailles de cacao ont démontré un bon potentiel pour le traitement d’effluents agro-alimentaires fortement chargés (DCOtot 3000–6000 mg·L–1). Les résultats obtenus montrent que les performances épuratoires des écailles sont inférieures à celles du support plastique. Les écailles de cacao doivent également être remplacées à une fréquence d’environ une fois toutes les 2 à 3 semaines. Toutefois, les boues produites par le traitement, composées d’écailles usées et de biomasse, sont riches en azote et peu contaminées et sont donc potentiellement valorisables en agriculture ou par compostage.
OCULAR TEMPERATURE DISTRIBUTION: A MATHEMATICAL PERSPECTIVE
Authors: OOI E. H. , NG E. Y. K.
Published: June 2009

Mathematical modeling has proven to be a viable alternative for investigating the temperature distribution inside the human eye. This is due to its ability to overcome the limitations infrared (IR) thermography; the leading method in ocular temperature measurement. A wide range of mathematical studies on the ocular temperature distribution during various conditions have been published in the literature. In this paper, we carry out an in-depth review of the various mathematical models of the eye that have been developed in the past. Various problems and the implications from the mathematical predictions of these studies are discussed. The future directions of studies in ocular temperature distribution are deliberated.
Governance Structures and Resource Policy Reform: Insights from Agricultural Transition
Authors: Swinnen Johan F.M. , Rozelle Scott
Published: June 2009

New research on the political economy of policy-induced distortions to incentives for optimal resource use in agriculture and insights from the study of the dramatic reforms in former state-controlled economy has led to enhanced insights on the role of governance structures on policy making in agricultural and natural resources. This paper reviews these research developments and key new insights.
Preactivation of NKT cells with α-GalCer protects against hepatic ischemia-reperfusion injury in mouse by a mechanism involving IL-13 and adenosine A2Areceptor
Authors: Cao Zongxian , Yuan Youzhong , Jeyabalan Geetha , Du Qiang , Tsung Allan , Geller David A. , Billiar Timothy R.
Published: June 2009

Hepatic preconditioning has emerged as a promising strategy of activating natural pathways to augment tolerance to liver ischemia-reperfusion (IR) injury. Liver-resident natural killer T (NKT) cells play an important role in modulating the local immune and inflammatory responses. This work was aimed to investigate whether preactivation of NKT cells could provide a beneficial “preconditioning” effect to ameliorate the subsequent hepatic IR injury. To selectively activate NKT cells, C57BL/6 mice were treated intraperitoneally with the glycolipid antigen α-galactosylceramide (α-GalCer) 1 h prior to hepatic ischemia. Significantly reduced liver IR injury was observed in mice pretreated with α- GalCer, and this protective effect was specifically abrogated by a CD1d blocking antibody. Serum TNF-α, IFN-γ, and IL-13 levels were markedly increased shortly after α-GalCer injection. Pretreatment with a neutralizing antibody against TNF-α or IFN-γ did not influence the protective effect of α-GalCer preconditioning, whereas preadministration of an IL-13 neutralizing antibody completely abolished the effect. Treatment with α-GalCer also led to an increased expression of adenosine A2Areceptor (A2AR) in the liver, and blockade of A2AR by SH58261 diminished α-GalCer pretreatment-mediated attenuation of liver IR injury. In contrast, administration of the selective A2AR agonist CGS21680 reversed the counteracting effect of the IL-13 neutralizing antibody on α-GalCer preconditioning. Additionally, α-GalCer pretreatment was associated with a decreased neutrophil accumulation in the ischemic liver. These findings provide the first evidence that hepatic preconditioning by preactivation of NKT cells with α-GalCer protects the liver from IR injury via an IL-13 and adenosine A2AR-dependent mechanism.
Effects of the phases of the menstrual cycle on gastric emptying, glycemia, plasma GLP-1 and insulin, and energy intake in healthy lean women
Authors: Brennan Ixchel M. , Feltrin Kate L. , Nair Nivasinee S. , Hausken Trygve , Little Tanya J. , Gentilcore Diana , Wishart Judith M. , Jones Karen L. , Horowitz Michael , Feinle-Bisset Christine
Published: June 2009

There is evidence that the menstrual cycle affects appetite, such that energy intake is lower during the follicular compared with the luteal phase. Gastric emptying influences energy intake, glycemia, and plasma glucagon-like peptide-1 (GLP-1), insulin, and cholecystokinin (CCK) release. We hypothesized that 1) gastric emptying of a glucose drink is slower, and glycemia, plasma hormones, hunger, and energy intake are less, during the follicular compared with the luteal phase; 2) the reduction in the latter parameters during the follicular phase are related to slower gastric emptying; and 3) these parameters are reproducible when assessed twice within a particular phase of the menstrual cycle. Nine healthy, lean women were studied on three separate occasions: twice during the follicular phase ( days 6- 12) and once during the luteal phase ( days 18- 24). Following consumption of a 300-ml glucose drink (0.17 g/ml), gastric emptying, blood glucose, plasma hormone concentrations, and hunger were measured for 90 min, after which energy intake at a buffet meal was quantified. During the follicular phase, gastric emptying was slower ( P < 0.05), and blood glucose ( P < 0.01), plasma GLP-1 and insulin ( P < 0.05), hunger ( P < 0.01), and energy intake ( P < 0.05) were lower compared with the luteal phase, with no differences for CCK or between the two follicular phase visits. There were inverse relationships between energy intake, blood glucose, and plasma GLP-1 and insulin concentrations with the amount of glucose drink remaining in the stomach at t = 90 min ( r < −0.6, P < 0.05). In conclusion, in healthy women 1) gastric emptying of glucose is slower, and glycemia, plasma GLP-1 and insulin, hunger, and energy intake are less during the follicular compared with the luteal phase; 2) energy intake, glycemia, and plasma GLP-1 and insulin are related to gastric emptying; and 3) these parameters are reproducible when assessed twice during the follicular phase.
Roux-en-Y gastric bypass alters small intestine glutamine transport in the obese Zucker rat
Authors: Wolff Brynn S. , Meirelles Katia , Meng Qinghe , Pan Ming , Cooney Robert N.
Published: June 2009

The metabolic effects of Roux-en-Y gastric bypass (RYGB) are caused by postsurgical changes in gastrointestinal anatomy affecting gut function. Glutamine is a critical gut nutrient implicated in regulating glucose metabolism as a substrate for intestinal gluconeogenesis. The present study examines the effects of obesity and RYGB on intestinal glutamine transport and metabolism. First, lean and obese Zucker rats (ZRs) were compared. Then the effects of RYGB and sham surgery with pair feeding (PF) in obese ZRs were studied. Segments of small intestine (biliopancreatic limb, Roux limb, and common channel) mucosa were harvested and brush border membrane vesicles (BBMVs) were isolated on postoperative day 28. Glutamine transporter activity and abundance, B0AT1 protein, and mRNA levels were measured. Levels of glutaminase, cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C), and glucose-6-phosphatase (G6Pase) were measured to assess glutamine metabolism and intestinal gluconeogenesis. Obesity increased glutamine transport and B0AT1 expression throughout the intestine. RYGB increased glutamine transport activity in the biliopancreatic (3.8-fold) and Roux limbs (1.4-fold) but had no effect on the common channel. The relative abundance of B0AT1 mRNA and protein were increased in the biliopancreatic (6-fold) and Roux limbs (10-fold) after RYGB ( P < 0.05 vs. PF), but not the common channel. Glutaminase levels were increased, whereas the relative abundance of PEPCK-C and G6Pase were decreased in all segments of intestine after RYGB. RYGB selectively increased glutamine absorption in biliopancreatic and Roux limbs by a mechanism involving increased B0AT1 expression. Post-RYGB glutaminase levels were increased, but the reductions in PEPCK-C and G6Pase suggest that RYGB downregulates intestinal gluconeogenesis.