[en] Full text: In this prospective study, we assessed the value of ⁹⁹Tc^m-tetrofosmin and ¹²³I whole-body imaging in well differentiated thyroid cancer (WDTC). 59 sequential patients (M = 10, F 39) with WDTC at initial presentation (n = 13) or follow-up (n = 46) were scanned with ⁹⁹Tc^m-tetrofosmin (∼ 370 MBq) at 30 min and ¹²³I (∼ 700 MBq) after 48 h Whole-body images and spot views of the neck were performed with both tracers. The TSH ranged from 11.4 to 159 (median 48.5) and thyroglobulin (TG) from < 0.2 to 31,068.0 (median 12.5). Studies were interpreted by two independent observers on two occasions. Disagreement was resolved by consensus. For follow-up patients, true-negatives were defined as TG < 2, a negative ¹³¹I therapy study (where performed) and no clinical/radiological evidence of disease; true-positives were defined as TG > 2, a positive ¹³¹I therapy study or clinical/radiological evidence of disease. In the immediate postsurgery group, the sensitivity for detection of thyroid remnant was ¹²³I = 100%, tetrofosmin = 77%. In the post-ablative group, the sensitivities were ¹²³I = 60.6% and tetrofosmin = 36.3%; the specificities were 69.3% and 76.9%. Analysis of the number of lesions identified at each anatomical site (thyroid bed, cervical/neck, chest/mediastinum, skeletal, other) was performed, Of the 54 sites of disease identified on the ¹³¹I-therapy scan, 49 (91%) were identified by ¹²³I scan and 24 (44%) with tetrofosmin study. In conclusion, ¹²³I is definitely superior to ⁹⁹Tc^m-tetrofosmin in the detection of residual disease in follow-up patients with WDTC

[en] Thyroid trapping index of ^99mTc pertechnetate (neck to thigh ratio) has been used for several decades as a simple alternative to thyroid uptake. Using a trapping index normal range of less than 6, several patients with subjectively diffuse increase in thyroid trapping, biochemical hyperthyroidism and clinical features of thyrotoxicosis have been classified as normal. Three thyroid function calculation methods were used in 43 patients: 1. thyroid trapping index calculated from the total counts in the neck and thigh images - method A, 2. thyroid trapping index calculated from thyroid region of interest (ROI) counts and ROI transposition over the thigh - method B, 3. standard based percentage thyroid uptake - method C. Five patients (11.6%) were shown to be hyperthyroid by thyroid uptake while trapping index was within normal limits. Correlation amongst all three methods was excellent with methods A and B showing a 0.9870 correlation coefficient, methods A and C a 0.9859 correlation coefficient and methods B and C a 0.9804 correlation coefficient. All 3 methods were shown to provide valid measures of thyroid function. The normal range for trapping index was modified after correlation with the standard thyroid uptake normal limits. Copyright (2003) The Australian and New Zealand Society of Nuclear Medicine Inc

[en] Liquid-liquid extraction is essential to the spent nuclear fuel reprocessing industry, and future more efficient plants will require the development of increasingly selective chemical processes. Interactions between the actinides and organic ligands must be better understood for this purpose, particularly near liquid-liquid interfaces. We therefore undertook to develop a measuring instrument combining sensitivity and spatial localization for spectroscopic analysis of this particular zone. The standard nuclearization requirements concerning such instruments led us to develop a far-field optical system with the desired sensitivity, but its spatial localization potential was too adversely impacted by interface fluid movements. In the light of the experimental findings we have reexamined the measurement and nonelectoral options. (authors)

[en] In line with the salt-alkalinized soils found in the northeast of China, the conditions were simulated to investigate the mechanisms associated with this combination of stresses on Melilotus officinalis. The effects of salinity (NaCl: 0-300mM) in combination with alkali (pH: 7.1-9.8) on the seed germination and seedlings of M. officinalis were investigated. The results showed that germination was not inhibited completely by the salt-alkali conditions tested. The recovery germinations were significant higher than the control or had no significant differences with the control under the conditions of NaCl less than 200mM and pH=9.0, suggesting that non-germinated seeds may have a strategy to get through and resist the stress during germination stage. For the seedling growth, M. officinalis was capable of surviving at high pH (pH=9.8) and the salinity (NaCl=200mM) (seedling survival rate: 84.77 ± 8.62 percentage). The characteristic feature for combined salt-alkali stresses is the reciprocal enhancement between salt and alkali stresses. The combined action of salinity and pH should be considered when evaluating the effects of salt-alkali stresses. Correlation and regression analyses showed that salinity was the dominant stress factor, while pH was a secondary factor. From the physiological and ecological parameters, we suggested that M. officinalis is a salt-alkali tolerant species which can be used in vegetative restoration of saline soils in the northeast of China. (author)

[en] Full text: Spiral CT (SCT) has been advocated as a replacement for pulmonary angiography (PA)in patients with intermediate probability (IP) ventilation-perfusion lung scans (V/Q). More generally it has been proposed as a replacement for V/Q to detect Pulmonary Embolism. This study investigates the accuracy of SCT in the IP patient group 31 patients with IP scans (Modified PIOPED criteria) who were not at high risk of contrast nephrotoxicity were enrolled to have both SCT and PA within the 24 hours following their V/Q. Patients were classified as IP due to a single segmental mismatch (n=7) or a matched V/Q abnormality corresponding to CXR opacity (n=21), or both (n=3). PA is the gold standard for the detection of PE. SCT was read by an experienced radiologist blinded to the PA results. SCT was performed according to standard protocol. All SCT were technically satisfactory for interpretation. Pulmonary embolism was present in 9/31 patients (29%). Of the patients with PE detected by PA, SCT was positive in 4 (44% sensitivity). Of the 22 patients who did not have PE, SCT was negative in 21 and positive in one (96% specificity). In conclusion SCT has limited sensitivity for the detection of PE in patients with IP lung scans. SCT may not be an adequate replacement for PA. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

[en] A robust multi-fidelity design algorithm has been developed, focusing to efficiently handle industrial hydraulic runner design considerations. The computational task is split between low- and high-fidelity phases in order to properly balance the CFD cost and required accuracy in different design stages. In the low-fidelity phase, a derivative-free optimization method employs an inviscid flow solver to obtain the major desired characteristics of a good design in a relatively fast iterative process. A limited number of candidates are selected among feasible optimization solutions by a newly developed filtering process. The main function of the filtering process is to select some promising candidates to be sent into the high-fidelity phase, which have significantly different geometries, and also are dominant in their own territories. The high-fidelity phase aims to accurately evaluate those promising candidates in order to select the one which is closest to design targets. A low-head runner case study has shown the ability of this methodology to identify an optimized blade through a relatively low computational effort, which is significantly different from the base geometry

[en] We investigate the dissolution law of metallic nanoparticles (NPs) under sustained irradiation. The system is composed of isolated spherical gold NPs (4–100 nm) embedded in an amorphous silica host matrix. Samples are irradiated at room temperature in the nuclear stopping power regime with 4 MeV Au ions for fluences up to 8 × 10"1"6" cm"−"2. Experimentally, the dependence of the dissolution kinetics on the irradiation fluence is linear for large NPs (45–100 nm) and exponential for small NPs (4–25 nm). A lattice-based kinetic Monte Carlo (KMC) code, which includes atomic diffusion and ballistic displacement events, is used to simulate the dynamical competition between irradiation effects and thermal healing. The KMC simulations allow for a qualitative description of the NP dissolution in two main stages, in good agreement with the experiment. Moreover, the perfect correlation obtained between the evolution of the simulated flux of ejected atoms and the dissolution rate in two stages implies that there exists an effect of the size of NPs on their dissolution and a critical size for the transition between the two stages. The Frost-Russell model providing an analytical solution for the dissolution rate, accounts well for the first dissolution stage but fails in reproducing the data for the second stage. An improved model obtained by including a size-dependent recoil generation rate permits fully describing the dissolution for any NP size. This proves, in particular, that the size effect on the generation rate is the principal reason for the existence of two regimes. Finally, our results also demonstrate that it is justified to use a unidirectional approximation to describe the dissolution of the NP under irradiation, because the solute concentration is particularly low in metal-glass nanocomposites

[en] This paper presents a CFD-based methodology for the prediction of guide vane torque in hydraulic turbine distributors for synchronized and desynchronized configurations. A desynchronized configuration occurs when the opening angle of one guide vane differs from the opening angle of all other guide vanes, which may lead to a torque increase on neigbouring guide vanes. A fully automated numerical procedure is presented, that automates computations for a complete range of operation of a distributor. Results are validated against laboratory measurements.

[en] For the first time, the nanoflower-like zinc borate compound was obtained by precipitation at room temperature using zinc oxide nanoparticles as a precursor. The obtained zinc borates were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), thermal gravimetric analysis (TGA), and Raman spectroscopy analysis. Monoclinic of zinc borate 2ZnO. 3B₂O₃.3.5H₂O was achieved under the XRD pattern and the elemental chemical analysis. The particle size of the obtained materials is approximately 5 nm using TEM analysis. The TGA shows that the achieved zinc borate is outstanding stable at high temperatures. The result of this work provides a new route for the fabrication of zinc borate nanoparticle, which could be widely used in many applications. (paper)

[en] Nowadays, computational fluid dynamics is commonly used by design engineers to evaluate and compare losses in hydraulic components as it is less expensive and less time consuming than model tests. For that purpose, an automatic tool for casing and distributor analysis will be presented in this paper. An in-house mesh generator and a Reynolds Averaged Navier-Stokes equation solver using the standard k-ω SST turbulence model will be used to perform all computations. Two solvers based on the C++ OpenFOAM library will be used and compared to a commercial solver. The performance of the new fully coupled block solver developed by the University of Lucerne and Andritz will be compared to the standard 1.6ext segregated simpleFoam solver and to a commercial solver. In this study, relative comparisons of different geometries of casing and distributor will be performed. The present study is thus aimed at validating the block solver and the tool chain and providing design engineers with a faster and more reliable analysis tool that can be integrated into their design process