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31.
32.
Ochratoxin A in dried vine fruit: method development and survey   总被引:7,自引:0,他引:7  
A method is described for the determination of concentrations of the mycotoxin ochratoxin A in dried vine fruits (currants, raisins and sultanas) using acidic methanolic extraction,immunoaffinity chromatography clean-up and HPLC determination. The limit of detection was estimated as 0.2mug/kg, and recoveries of 63-77% were achieved at 5mug/kg. HPLC-mass spectrometric confirmation of the identity of ochratoxin was obtained. Ochratoxin A and aflatoxins were determined in 60 samples of retail dried vine fruits purchased in the United Kingdom. Ochratoxin A was found in excess of 0.2mug/kg in 19 of 20 currant, 17 of 20 sultana and 17 of 20 raisin samples examined, an overall incidence of 88% . The maximum level found was 53.6mug/kg. No aflatoxin was found in any sample analysed, using a method with a detection limit of 0.2mug/kg for each of aflatoxin B1, B2, G1 and G2.  相似文献   
33.
Unified RF requirements are derived for an UMTS Terrestrial RadioAccess/Frequency Division Duplex (UTRA/FDD) compliant mobile transceiver. Aset of transceiver requirements are proposed with consideration to systemissues including duplex aspects. From these design-compatible requirements areproposed for each functional block in the transceiver.  相似文献   
34.
A new analytic model is presented (the model is based on the induced current density distribution inside silicon substrate) to calculate frequency dependent mutual inductance and resistance per unit length of coupled on-chip interconnects in CMOS technology. The validity of the proposed model has been checked by a comparison with a quasi-TEM spectral domain numerical simulation and equivalent-circuit modeling procedure. It is found that the silicon semiconducting substrate skin effect must be considered for the accurate prediction of the high-frequency characteristics of VLSI interconnects.  相似文献   
35.
Spinal cord injury (SCI) often results in a cavitary lesion, contained within the dura, which involves only a portion of the cord. Injectable biopolymers are an attractive treatment option for SCI to re‐establish cell migratory pathways within the lesion while minimizing the collateral damage attendant to an open surgical procedure. In this study we evaluate a thermoresponsive soluble collagen gel incorporating genipin, an amine reactive covalent cross‐linker with low cytotoxicity and fluorogenic attributes. Unlike previous studies, genipin is being investigated as an in situ covalent cross‐linker that will continue to act on the gel after injection. Physical characterization studies show that the addition of genipin provides control over the mechanical and degradative behavior of the gel, to meet design specifications of an injectable material for neural tissues. Additionally, an improved in situ assay to predict the extent of cross‐linking reaction is investigated. Encapsulation of mesenchymal stem cells (MSCs) in collagen–genipin gels show the gels support cell viability and proliferation, and thus serve as a cell delivery vehicle. Neural stem cells are found to be more sensitive to genipin, with respect to toxicity, as compared to MSCs. From our studies, 0.25‐0.5 mM is an appropriate genipin concentration to use for an in situ forming scaffold capable of delivering cells and therapeutic agents.  相似文献   
36.
Reverberation chambers can be used to measure the absorption cross section of a dielectric object. The absorption cross section of a dielectric object depends on its size, shape, and electrical material parameters. By comparing with a theoretical model of the absorption cross section, material parameters can be extracted from measurements. A model based on a plane wave approach of incident fields is used here, valid for electrically large material samples in an isotropic environment such as that in a reverberation chamber. Which material parameter can be extracted depends on the properties of the material sample. The presented method combines the accuracy of cavity methods with the flexibility of being able to measure samples of arbitrary size and shape. Because both the reverberation chamber and the material sample are electrically large, the method is particularly useful at millimeter-wave frequencies.  相似文献   
37.
The design and preparation of isotropic silver nanowire‐polystyrene composites is described, in which the nanowires have finite L/D (< 35) and narrow L/D distribution. These model composites allow the L/D dependence of the electrical percolation threshold, ?c, to be isolated for finite‐L/D particles. Experimental ?c values decrease with increasing L/D, as predicted qualitatively by analytical percolation models. However, quantitative agreement between experimental data and both soft‐core and core–shell analytical models is not achieved, because both models are strictly accurate only in the infinite‐L/D limit. To address this analytical limitation, a soft‐core simulation method to calculate ?c and network conductivity for cylinders with finite L/D are developed. Our simulated ?c results agree strongly with our experimental data, suggesting i) that the infinite‐aspect‐ratio assumption cannot safely be made for experimental networks of particles with L/D < 35 and ii) in predicting ?c, the soft‐core model makes a less significant assumption than the infinite‐L/D models do. The demonstrated capability of the simulations to predict ?c in the finite‐L/D regime will allow researchers to optimize the electrical properties of polymer nanocomposites of finite‐L/D particles.  相似文献   
38.
BM3D frames and variational image deblurring   总被引:2,自引:0,他引:2  
A family of the block matching 3-D (BM3D) algorithms for various imaging problems has been recently proposed within the framework of nonlocal patchwise image modeling , . In this paper, we construct analysis and synthesis frames, formalizing BM3D image modeling, and use these frames to develop novel iterative deblurring algorithms. We consider two different formulations of the deblurring problem, i.e., one given by the minimization of the single-objective function and another based on the generalized Nash equilibrium (GNE) balance of two objective functions. The latter results in the algorithm where deblurring and denoising operations are decoupled. The convergence of the developed algorithms is proved. Simulation experiments show that the decoupled algorithm derived from the GNE formulation demonstrates the best numerical and visual results and shows superiority with respect to the state of the art in the field, confirming a valuable potential of BM3D-frames as an advanced image modeling tool.  相似文献   
39.
Rosemary (dried leaves ofRosmarinus officinalis L.) added to cooked meat balls (minced pork) was found to retard the formation of warmed over flavour (WOF) during chill storage. The spice was added to pork meat (Longissimus dorsi) balls in an amount acceptable for the product, as evaluated by a sensory panel (0.05% of total weight). After cooking (water bath, internal temperature 80°C), the meat balls were packed using five atmosphere packaging conditions: (i) air; (ii) 5% O2/95% N2; (iii) 3% O2/97% N2; (iv) 1% O2/99% N2; and (v) 100% N2. During chill storage (5°C), the sensory quality of the reheated meat balls was evaluated by a trained sensory panel, and lipid oxidation was followed by measurement of thiobarbituric acid reactive substances (TBARS). The combination of decreased O2 atmosphere in the packages and addition of rosemary resulted in a significantly (p<0.05) lower amount of TBARS and a significantly (p<0.05) better sensory score.
Gemeinsamer Effekt von Rosmarin (Rosmarinus officinalis L.) und Verpackung in modifizierter Atmosphäre auf den Aufwärmegeschmack (WOF) von wärmebehandeltem, gehacktem Schweinefleisch
Zusammenfassung Rosmarin (getrocknete Blätter vonRosmarinus officinalis L.), erwärmten Fleischklößen (gehacktes Schweinefleisch) zugesetzt, hinderte die Entwicklung des Aufwärmgeschmacks (warmed over flavour) während der Kühllagerung. Das Gewürz wurde den aus Schweinefleisch (Longissimus dorsi) hergestellten Fleischklößen in einer für das Produkt akzeptablen Menge zugegeben, beurteilt von einem sensorischen Panel (0.05% des Totalgewichtes). Nach der Wärmebehandlung (Wasserbad, Zentrum-Temperatur 80°C) wurden die Fleischklöße in fünf unterschiedlichen und kontrollierten Atmosphären wie folgt verpackt: (i) Luft; (ii) 5% O2/95% N2; (iii) 3% O2/97% N2; (iv) 1% O2/99% N2 und (v) 100% N2. Während der Kühllagerung (5°C) wurde die sensorische Qualität der wiedererwärmten Fleischklöße von einem geschulten Panel beurteilt und die Lipid-Oxidation durch Messung der Thiobarbitursäure-reaktiven Substanzen (TBARS) beobachtet. Die Kombination von ermäßigtem Sauerstoffgehalt in den Verpackungen mit der Zugabe von Rosmarin ergab eine signifikant (p<0.05) niedrigere Menge TBARS wie auch signifikant (p<0.05) bessere Punkte in der sensorischen Beurteilung.
  相似文献   
40.
Vertical arrays of nanostructures (NSs) are emerging as promising platforms for probing and manipulating live mammalian cells. The broad range of applications requires different types of interfaces, but cell settling on NS arrays is not yet fully controlled and understood. Cells are both seen to deform completely into NS arrays and to stay suspended like tiny fakirs, which have hitherto been explained with differences in NS spacing or density. Here, a better understanding of this phenomenon is provided by using a model that takes into account the extreme membrane deformation needed for a cell to settle into a NS array. It is shown that, in addition to the NS density, cell settling depends strongly on the dimensions of the single NS, and that the settling can be predicted for a given NS array geometry. The predictive power of the model is confirmed by experiments and good agreement with cases from the literature. Furthermore, the influence of cell‐related parameters is evaluated theoretically and a generic method of tuning cell settling through surface coating is demonstrated experimentally. These findings allow a more rational design of NS arrays for the numerous exciting biological applications where the mode of cell settling is crucial.  相似文献   
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