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921.
This study quantified the impact of the well-known physiologic noise correction algorithm RETROICOR applied to a pain functional magnetic resonance imaging (FMRI) experiment at two field strengths: 1.5 and 3.0 T. In the 1.5-T acquisition, there was an 8.2% decrease in time course variance (σ) and a 227% improvement in average model fit (increase in mean R2a). In the 3.0-T acquisition, significantly greater improvements were seen: a 10.4% decrease in σ and a 240% increase in mean R2a. End-tidal carbon dioxide data were also collected during scanning and used to account for low-frequency changes in cerebral blood flow; however, the impact of this correction was trivial compared to applying RETROICOR. Comparison between two implementations of RETROICOR demonstrated that oversampled physiologic data can be applied by either downsampling or modification of the timing in the RETROICOR algorithm, with equivalent results. Furthermore, there was no significant effect from manually aligning the physiologic data with corresponding image slices from an interleaved acquisition, indicating that RETROICOR accounts for timing differences between physiologic changes and MR signal changes. These findings suggest that RETROICOR correction, as it is commonly implemented, should be included as part of the data analysis for pain FMRI studies performed at 1.5 and 3.0 T. 相似文献
922.
Monitoring the enforcement of an EU-wide ban of nitrofuran antibiotics in the food production chain is a challenging task,
given the nature of nitrofuran compounds. The original and modified Fenton reactions are advanced oxidation processes that
can eliminate the toxicity of nitrofurans. 2-(5-Nitrofuryl)acrylic acid (I) was degraded as a model compound by the original Fenton reaction with ferrous sulphate, by Mohr’s salt at pH 3 and 7, and
finally by advanced Fenton process (AFP) (Fe0/H2O2/H2SO4). In addition, the growth inhibition of Escherichia coli, a G− bacterium, was tested both before and after AFP treatment. The results showed that a small degradation efficiency of this
treatment process led to the toxicity changes and that the toxicity of I after AFP treatment process decreased. It seems that the treatment of polluted water using the Fenton reaction and its modifications
would be a suitable method for degradation of nitrofuran derivatives in polluted water. 相似文献
923.
Repeatability standard deviation, laboratory standard deviation, and reproducibility standard deviation for quantitative methods
according to ISO 5725 series were recently proposed to estimate the precision of qualitative measurements, giving a presence/absence
response. In this paper, it is shown that for qualitative methods, the reproducibility standard deviation across laboratories
does not reflect the performance of the method as suggested. It is demonstrated that the benefit of the respective laboratory
standard deviation is very limited. Alternative performance measures are introduced which are based on another approach also
directly linked to ISO 5725. Thereby, meaningful information about the precision of qualitative test methods can be achieved. 相似文献
924.
The interaction of the cationic drug rivanol (RIV) with three types of surfactants; [cationic (cetyltrimethylammonium bromide; CTAB), anionic (sodium dodecylsulfate; SDS), and nonionic (t‐octylphenoxypolyethoxyethanol, TX‐100)] has been studied spectrophotometrically as a function of surfactant concentration from the premicellar to the postmicellar region. A comparison of the binding constants calculated from the Benesi–Hildebrand equation indicated that the binding tendency of RIV with TX‐100 micelles is higher than that with SDS micelles. The binding constants of RIV to both SDS and TX‐100 micelles were found to decrease in the presence of NaCl (0.225% w/v), ethanol (5% v/v), propylene glycol (5% v/v), and glycerin (5% v/v), The addition of the additives to the medium had a pronounced effect on the association of RIV with micelles. They all tended to decrease the binding of RIV to micelles. The inhibitory effect of alcohols followed the order water>glycerin>propylene glycol>ethanol. 相似文献
925.
Jürgen Pionteck Maria Omastová Petra Pötschke Frank Simon Ivan Chodák 《Journal of Macromolecular Science: Physics》2013,52(5-6):737-748
An electrical-conducting polypropylene/polypyrrole (PP/PPy) composite was prepared by the chemically oxidative modification reaction of pyrrole on the surface of PP particles in suspension. Another type of PP/PPy composite was prepared by mixing the coated PP particles with noncoated PP particles at room temperature. The composites were processed by compression molding or by injection molding. The injection-molded composites exhibited better mechanical properties compared to compression-molded samples, while these composites showed better antistatic behavior and electrical conductivity. The differences in the behavior of the two types of composites were caused by the different structure of the PPy phase, which was studied by hot-stage optical microscopy and X-ray photoelectron spectroscopy (XPS). 相似文献
926.
A metal-free catalytic method for the conversion of aromatic and aliphatic aldoximes to nitriles at room temperature using oxalyl chloride (1.2 equiv) in combination with 5 mol % of triphenylphosphine oxide is reported. Of the many potential pathways leading from oxime to nitrile a manifold involving chlorophosphonium salt-catalysed decomposition of oxime chlorooxalates formed in situ is shown to be operative. 相似文献
927.
Erika Švara Fabjan Andrijana Sever Škapin Luka Škrlep Petra Živec Miran Čeh Miran Gaberšček 《Journal of Sol-Gel Science and Technology》2012,62(1):65-74
A model organic pigment (β copper phthalocyanine) was encapsulated by silica using water glass as a precursor. It is shown
that the thickness, porosity and uniformity of silica shells (coatings) around individual pigment particles depend significantly
on pH and temperature of synthesis. It is further demonstrated that the obtained silica shells can serve as an efficient protection
against the highly reactive products of photocatalysis. The degree of protection depends not only on the thickness of silica
shells but also on their porosity. 相似文献
928.
Annals of Combinatorics - For a given w in a Coxeter group W, the elements u smaller than w in Bruhat order can be seen as the end alcoves of stammering galleries of type w in the Coxeter complex... 相似文献
929.
930.