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31.
P. Vašek P. Svoboda V. Novák M. Cukr Z. Výborný V. Jurka J. Stuchlík M. Orlita D. K. Maude 《Journal of Superconductivity and Novel Magnetism》2010,23(6):1161-1163
The angular dependence of the magnetoresistance has been studied for two sets of samples: annealed and hydrogenated, respectively.
Different behavior of magnetoresistance anisotropy has been discussed in terms of change of scattering rate and/or introduction
of strain during treatment. 相似文献
32.
V Havlícek C Kieburg P Novák K Bezouska TK Lindhorst 《Canadian Metallurgical Quarterly》1998,33(7):591-598
Post-source decay (PSD) matrix-assisted laser desorption/ionization time-of-flight mass spectra were found to be useful for the structural elucidation of a series of tris [2-(glycosylthiourylene)ethyl]amines. The reported fragmentation behaviours of [M + H]+, [M + Na]+ and [M - H]- ions differ from each other significantly; however, they can be compared to tree pruning in every case. Whereas detailed structural information on unprotected glycoclusters is obtained from all PSD experiments, only the positive-ion mode can be used to gain relevant information about the acetylated glycoclusters. 相似文献
33.
R Beeri N Le Novère R Mervis T Huberman E Grauer JP Changeux H Soreq 《Canadian Metallurgical Quarterly》1997,69(6):2441-2451
In a search for behavioral, neuroanatomical, and metabolic characteristics of Alzheimer's disease that may result from cholinergic malfunction, we used transgenic mice overexpressing acetylcholinesterase (AChE) mRNA and active enzyme in brain neurons. Mapping by in situ hybridization revealed that transgenic and host AChE mRNAs were distributed similarly. In a Morris water maze working memory paradigm, adult transgenic mice did not display the characteristic improvement found in control mice either between or within test days and spent less time than control mice in the platform zone. In 5-week-old transgenic mice, the basilar dendritic trees of layer 5 pyramidal neurons from the frontoparietal cortex were essentially as developed as in age-matched controls. However, branching totally ceased after this age, whereas in control adults it continued up to at least 7 months. Therefore, dendritic arbors became smaller in adult transgenic mice than those of controls. Furthermore, the average number of spines was significantly lower on dendritic branches of 7-month-old but not 5-week-old transgenics as compared with controls. Binding of tritiated hemicholinium-3, a blocker of the high-affinity choline uptake characteristic of active cholinergic terminals, was over twofold enhanced in the brain of transgenic mice. In contrast, no differences were observed in the mRNA and ligand binding levels of several different subtypes of nicotinic and muscarinic acetylcholine receptors. These findings suggest that three different hallmarks associated with Alzheimer's disease--namely, progressive cognitive failure, cessation of dendrite branching and spine formation, and enhanced high-affinity choline uptake--are outcomes of cholinergic malfunction. 相似文献
34.
The determination of opiates in urine by thin layer chromatography may be difficult for the low concentrations of opiates and their mixtures. The result of the analysis is influenced by the isolation recovery, sensitivity of detection and by the choice of the chromatographic conditions for the separation of opiate mixtures. The study of these factors resulted in several modifications of routinely used method, so that the results are reliable for the concentration of opiates in urine 1 mg/l. Nevertheless, for the analysis of opiates in drug abuse control the comparison of thin layer chromatography findings with other chromatographic methods or immunoassays is important for the improvement of the laboratory performance and for the interpretation of the results. 相似文献
35.
Strohalm M Strohalm J Kaftan F Krásný L Volný M Novák P Ulbrich K Havlíček V 《Analytical chemistry》2011,83(13):5458-5462
Traditional tissue-sectioning techniques for histological samples utilize various embedding media to stabilize the tissue on a sectioning target and to provide a smooth cutting surface. Due to the ion suppression effect in MALDI ionization and number of background peaks in the low-mass region, these media are not suitable for mass spectrometry imaging (MSI) experiments. To overcome this, droplets of water are often used to mount the tissue on a sectioning target, but the ice block formed around the tissue does not provide a good support for sectioning of fragile samples. In this work, we propose a novel embedding media, compatible with MALDI ionization and MSI experiments, based on poly[N-(2-hydroxypropyl)methacrylamide] (pHPMA). Using a reversible addition-fragmentation chain transfer polymerization technique, well-defined pHPMA polymer with narrow mass distribution was prepared. Benefits of the resulted pHPMA-based embedding media were tested on different tissue samples. 相似文献
36.
Genevet P Tetienne JP Blanchard R Kats MA Müller JP Scully MO Capasso F 《Applied optics》2011,50(31):G56-G62
We present detailed experimental and numerical investigations of resonances in deep nanogroove gratings in metallic substrates. These plasmonic nanocavity gratings feature enhanced fields within the grooves that enable a large enhancement of linear and nonlinear optical processes. This enhancement relies on both localized and propagating surface plasmons on the nanopatterned surface. We show that the efficiency of optical processes such as Raman scattering and four-wave mixing is dramatically enhanced by plasmonic nanocavity gratings. 相似文献
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