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31.
Nagy P Bakonyi G Bongers T Kádár I Fábián M Kiss I 《The Science of the total environment》2004,320(2-3):131-143
Long-term effects of Cd, Cr, Cu, Se and Zn were studied 7 years after artificially contaminating plots of an agricultural field on a calcareous chernozem soil. Effects of three to four different contamination levels (originally 10, 30, 90 and 270 mg kg−1) were studied. Nematode density was significantly reduced by 90 and 270 mg kg−1 Se as well as by 270 mg kg−1 Cr, while 90 and 270 mg kg−1 Se also reduced nematode generic richness. Maturity Index values (calculated for c-p 2–5 nematodes) consistently decreased with increasing Cr and Se concentration and to a lesser extent in Zn plots as well. Structure Index showed decreasing trends in increasing Cr, Se and (to a lesser extent) in Zn treatments, while in Cd it shows a moderate increase. Distribution of c-p groups was negatively affected by the increasing Cr and Se concentration, while in Zn plots, this decrease was not significant. Response of feeding groups to pollutions was similar to other parameters: Cr and Se caused significant changes toward the loss of variability. The proportion of the most sensitive omnivorous and predatory nematodes decreased clearly as a consequence of Cr and Se treatments. Zn pollution also resulted in a slight decrease in this group, while Cd caused an increase. Nematode diversity profiles showed a significant decrease in the plots of increased Cr and Se concentrations, while increased concentrations of Cu and Zn resulted in ambiguous effects. Besides providing evidence on the harmful effects of Cr and Se on a soil nematode assemblage, our results suggest that simultaneous analysis of Maturity Index, Structure Index and diversity profiles provide a promising tool in nematological indication of soil pollution. 相似文献
32.
István Szőke Michael N. Louka Tom-Robert Bryntesen Svein-Tore Edvardsen Joachim Bratteli 《Journal of Nuclear Science and Technology》2013,50(3):371-387
There is an increasing international focus on the need to optimise decommissioning strategies, driven by the anticipation of high costs and major effort for the decommissioning of nuclear facilities in the coming decades. The goals are to control and mitigate costs and negative impacts on workers, the general public, and the environment. The methods presently employed for many decommissioning tasks do not apply the latest advancements of science and technology. Therefore, there is growing interest in research and development into the adoption of novel techniques for improving safety, reducing costs, and increasing transparency.This paper provides a comprehensive overview of the authors’ results from investigating how current and emerging technologies can be applied to enhance the international decommissioning strategy, focussing in particular on three-dimensional simulation, virtual reality, advanced user interfaces, mobile and wearable devices, and geographical information systems. Our results demonstrate that emerging technologies have great potential for supporting adoption of new instrumentation, improving data and knowledge management, optimising project plans, briefing and training field operators, and for communication, surveillance, and education in general. 相似文献
33.
Veselkov KA Vingara LK Masson P Robinette SL Want E Li JV Barton RH Boursier-Neyret C Walther B Ebbels TM Pelczer I Holmes E Lindon JC Nicholson JK 《Analytical chemistry》2011,83(15):5864-5872
Ultra-performance liquid chromatography coupled to mass spectrometry (UPLC/MS) has been used increasingly for measuring changes of low molecular weight metabolites in biofluids/tissues in response to biological challenges such as drug toxicity and disease processes. Typically samples show high variability in concentration, and the derived metabolic profiles have a heteroscedastic noise structure characterized by increasing variance as a function of increased signal intensity. These sources of experimental and instrumental noise substantially complicate information recovery when statistical tools are used. We apply and compare several preprocessing procedures and introduce a statistical error model to account for these bioanalytical complexities. In particular, the use of total intensity, median fold change, locally weighted scatter plot smoothing, and quantile normalizations to reduce extraneous variance induced by sample dilution were compared. We demonstrate that the UPLC/MS peak intensities of urine samples should respond linearly to variable sample dilution across the intensity range. While all four studied normalization methods performed reasonably well in reducing dilution-induced variation of urine samples in the absence of biological variation, the median fold change normalization is least compromised by the biologically relevant changes in mixture components and is thus preferable. Additionally, the application of a subsequent log-based transformation was successful in stabilizing the variance with respect to peak intensity, confirming the predominant influence of multiplicative noise in peak intensities from UPLC/MS-derived metabolic profile data sets. We demonstrate that variance-stabilizing transformation and normalization are critical preprocessing steps that can benefit greatly metabolic information recovery from such data sets when widely applied chemometric methods are used. 相似文献
34.
Csanády A Sajó I Lábár JL Szalay A Papp K Balaton G Kálmán E 《Journal of nanoscience and nanotechnology》2005,5(6):869-874
It is shown that pore-free bulk samples were produced by the high-energy rate forming axis-symmetrical powder compaction method for different application purposes in case of the very different, immiscible Al and Pb metal pair. The starting Al-Pb nanocomposites were made by mechanical milling of atomized Al and Pb powders either in a SPEX 9000 or a Fritsch Pulverisette 4 mill. Due to the conditions that milling was carried out in air, the PbO layer, originally existing at the surface of the atomized Pb powder, ruptured and was also dispersed in the composite. The presence of the nano PbO particles was proven by XRD and TEM (BF, DF, SAED). When the energy of milling was high, the PbO crystallites became so small that they could hardly be seen by XRD technique. Local distribution of the PbO nanoparticles was still visible in a TEM, using the process diffraction method. Both XRD and SAED proved to be useful for the evaluation of the results of the milling process and compaction. 相似文献
35.
It has been established by combined absorption and fluorescence measurements that the cationic dye Oxazine 1 (OX) and the polyvalent anionic host calix[8]arenesulfonate (SCA8) form two complexes in simultaneous reactions: OX + SCA8 <--> OX.SCA8 (1), and OX.SCA8 + OX <--> OX(2).SCA8 (2). The equilibrium constants for the two reactions, as functions of the ionic strength (I), and the absorption and fluorescence spectra of the two complex species have been determined by a least-squares fitting method from the experimental data. The variations of the binding constants with the ionic strength could be described on the basis of Debye-Huckel theory. The equilibrium constants are large; their values extrapolated to I = 0 are K(1) = 5.5 x 10(6) M(-1) and K(2) = 4.4 x 10(5) M(-1). The fluorescence of OX undergoes a strong static quenching upon complexation. These results indicate that the complexes are held together by strong electrostatic forces. The addition of non-fluorescent tetramethylammonium chloride to OX-SCA8 mixtures results in a dramatic fluorescent enhancement, which demonstrates the potential applicability of this supramolecular system in fluorescence assays. 相似文献
36.
Mórocz IA Janoos F van Gelderen P Manor D Karni A Breznitz Z von Aster M Kushnir T Shalev R 《International journal of imaging systems and technology》2012,22(1):81-96
The aim of this article is to report on the importance and challenges of a time-resolved and spatio-temporal analysis of fMRI data from complex cognitive processes and associated disorders using a study on developmental dyscalculia (DD). Participants underwent fMRI while judging the incorrectness of multiplication results, and the data were analyzed using a sequence of methods, each of which progressively provided more a detailed picture of the spatio-temporal aspect of this disease. Healthy subjects and subjects with DD performed alike behaviorally though they exhibited parietal disparities using traditional voxel-based group analyses. Further and more detailed differences, however, surfaced with a time-resolved examination of the neural responses during the experiment. While performing inter-group comparisons, a third group of subjects with dyslexia (DL) but with no arithmetic difficulties was included to test the specificity of the analysis and strengthen the statistical base with overall fifty-eight subjects. Surprisingly, the analysis showed a functional dissimilarity during an initial reading phase for the group of dyslexic but otherwise normal subjects, with respect to controls, even though only numerical digits and no alphabetic characters were presented. Thus our results suggest that time-resolved multi-variate analysis of complex experimental paradigms has the ability to yield powerful new clinical insights about abnormal brain function. Similarly, a detailed compilation of aberrations in the functional cascade may have much greater potential to delineate the core processing problems in mental disorders. 相似文献
37.
The last decade has brought marked changes in the surgical treatment of rectal cancer: as the indication of the sphincter-saving procedures was extended, the rate of the abdomino-perineal excision has decreased even in the case of tumours of the distal third of the rectum. However, even with the use of the modern stapling devices, the anterior resection and colo-anal anastomosis may not always be feasible by the traditional abdominal approach. In these cases the sphincter-saving resection can be performed by a particular approach, the abdomino-transsphincteric technique. The authors present this seldom used operation. From the 1-st of January 1994 to the 31-st of August 1996 14 abdomino-transsphincteric resections have been performed. The mean age of the patients was 62.2 (38-81) years. The lower edge of the tumours was situated at 6.3 (5-8) cm from the anal verge. The anastomosis was performed by the double stapling technique in 8 and by hand suture in 6 cases, its distance from the anal verge was 3.2 (3-4) cm. A colon J-pouch was used in 3 cases and a diverting colostomy was performed routinely. One patient died in the postoperative period and a reoperation (abdomino-perineal excission) was performed because of left colon necrosis: Anastomotic leakage was observed in one case. By the time of the present study, 11 patients have had their colostomies closed. The continence is acceptable in every case and all the patients experience a better subjective quality of life, than it was while wearing the colostomy. The use of this technique has helped to avoid a permanent colostomy in 21 out of 33 cases operated on for cancer of the distal rectal third in the reviewed period. 相似文献
38.
Miklós Tóth Walter Soares Leal István Szarukán Mátyás Lesznyák Gábor Szöcs 《Journal of chemical ecology》1994,20(10):2481-2487
Traps baited with 2-(E)-nonen-1-ol alone or in combination with other compounds caught large numbers of males of both the vine chafer,Anomala vitis Fabr. and the margined vine chafer,A. dubia Scop. (Coleoptera: Scarabaeidae), vineyard and orchard pests. In a dosage test, the largest numbers were caught by traps baited with 10 mg of 2-(E)-nonen-1-ol, which was the highest dosage tested. This is the first report on male attractants for chafer species occurring in Europe.The present paper is dedicated to the memory of our coauthor, friend and colleague Mátyás Lesznyák who died a premature and tragic death in late 1993. 相似文献
39.
Jenö Morgós Péter Sallay László Farkas István Rusznák 《Journal of the American Oil Chemists' Society》1986,63(9):1209-1210
Bridge-head nitrogen-containing compounds, (1,4-diaza-bicyclo-[2.2.2]-octane, 1-azabicyclo-[2.2.2]-octane, 1,5-diaza-bicyclo-[5.4.0]-undec-5-ene and l-azabicyclo-[2.2.2]-octane-3-one), successfully catalyze the ethoxylation of dodecyl alcohol. The catalytic activity of any of the first two compounds was four to five times higher than that of an open-chain, symmetrical trialkylamine of similar basicity. The molar mass distribution of the ethoxylated dodecyl alcohol derivatives was of the Weibull-Nycander-Gold type. No Weibull-Törnquist effect could be detected, however, unlike the case realized in ethoxylated systems gained in the presence of trialkylamines. No change in the distribution constant (calculated according to Natta and Mantica) could be observed in the course of these ethoxylation reactions. 相似文献
40.
Structural and Multidisciplinary Optimization - For a structure under service loads, there is a need to induce precise control of a local displacement by additional punch loading. Such problem... 相似文献