排序方式: 共有16条查询结果,搜索用时 15 毫秒
1.
Wijdeven MA Botman PN Wijtmans R Schoemaker HE Rutjes FP Blaauw RH 《Organic letters》2005,7(18):4005-4007
The stereoselective total synthesis of the novel quinolizidine alkaloid (+)-epiquinamide is presented, starting from the amino acid l-allysine ethylene acetal. Key steps in the synthesis involved a highly diastereoselective N-acyliminium ion allylation and a ring-closing metathesis reaction to provide the bicyclic skeleton. [reaction: see text] 相似文献
2.
Both Pt/Al2O3 and (Pt+Re)/Al2O3 industrial catalysts contain, after reduction (at 450 °C) ions, extractable by acetylacetone. However, a substantial part of Re is reduced.
Pt/Al2O3 (Pt+Re)/Al2O3 ( 450 °C) , . , .相似文献
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We discuss the notion of spin squeezing considering two mutually exclusive classes of spin-s states, namely, oriented and non-oriented states. Our analysis shows that the oriented states are not squeezed while non-oriented
states exhibit squeezing. We also present a new scheme for construction of spin-s states using 2s spinors oriented along different axes. Taking the case of s=1, we show that the ‘non-oriented’ nature and hence squeezing arise from the intrinsic quantum correlations that exist among
the spinors in the coupled state. 相似文献
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Hoen R Leleu S Botman PN Appelman VA Feringa BL Hiemstra H Minnaard AJ van Maarseveen JH 《Organic & biomolecular chemistry》2006,4(4):613-615
A BICOL derived monodentate phosphoramidite ligand gives ee's up to 89% in the enantioselective Rh-catalysed hydrogenation of N-acyl dehydroalanine using water as the solvent. 相似文献
7.
Thomas Fenzl Chadi Touma Christoph PN Romanowski Jörg Ruschel Florian Holsboer Rainer Landgraf Mayumi Kimura Alexander Yassouridis 《BMC neuroscience》2011,12(1):29
Background
Neuronal mechanisms underlying affective disorders such as major depression (MD) are still poorly understood. By selectively breeding mice for high (HR), intermediate (IR), or low (LR) reactivity of the hypothalamic-pituitary-adrenocortical (HPA) axis, we recently established a new genetic animal model of extremes in stress reactivity (SR). Studies characterizing this SR mouse model on the behavioral, endocrine, and neurobiological levels revealed several similarities with key endophenotypes observed in MD patients. HR mice were shown to have changes in rhythmicity and sleep measures such as rapid eye movement sleep (REMS) and non-REM sleep (NREMS) as well as in slow wave activity, indicative of reduced sleep efficacy and increased REMS. In the present study we were interested in how far a detailed spectral analysis of several electroencephalogram (EEG) parameters, including relevant frequency bands, could reveal further alterations of sleep architecture in this animal model. Eight adult males of each of the three breeding lines were equipped with epidural EEG and intramuscular electromyogram (EMG) electrodes. After recovery, EEG and EMG recordings were performed for two days. 相似文献8.
I. S. Guk A. N. Dovbnya S. G. Kononenko F. A. Peev A. S. Tarasenko M. van der Wiel J. I. M. Botman 《Physics of Particles and Nuclei Letters》2008,5(7):638-641
At the National Science Centre, Kharkiv Institute of Physics and Technology (NSC KIPT) the possibility of creating an installation
with a subcritical reactor driven by an electron accelerator is examined. To obtain the maximal stream of neutrons from a
neutron-producing target at a minimal density of energy emission, the electron energy should be in the range of 100–200 MeV
and the size of the target should be as large as possible. Other important requirements are beam continuity with time and
long-term stability of the accelerator parameters. The variants of using the superconducting linear accelerator on the basis
of a TESLA accelerating structure as of subcritical reactor driver are considered. The basic design parameters and characteristics
of this installation are presented.
The text was submitted by the authors in English. 相似文献
9.
MK Hossain-Ibrahim K Rezajooi JK MacNally MRJ Mason AR Lieberman PN Anderson 《BMC neuroscience》2006,7(1):8-21
Background
Inflammation around cell bodies of primary sensory neurons and retinal ganglion cells enhances expression of neuronal growth-associated genes and stimulates axonal regeneration. We have asked if inflammation would have similar effects on corticospinal neurons, which normally show little response to spinal cord injury. Lipopolysaccharide (LPS) was applied onto the pial surface of the motor cortex of adult rats with or without concomitant injury of the corticospinal tract at C4. Inflammation around corticospinal tract cell bodies in the motor cortex was assessed by immunohistochemistry for OX42 (a microglia and macrophage marker). Expression of growth-associated genes c-jun, ATF3, SCG10 and GAP-43 was investigated by immunohistochemistry or in situ hybridisation. 相似文献10.
C. A.?ThomasEmail author J. I.M.?Botman C.?Bruni G.?Orlandi G.?de Ninno D.?Garzella M. E.?Couprie 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2005,32(1):83-93
In a Storage Ring Free Electron Laser (SRFEL) there is a
strong interdependence between the laser beam and the electron
beam from which the laser is generated. The Super ACO storage ring
has a second Radio Frequency (RF) cavity at the 5th harmonic of
the main RF cavity. It is used to shorten the bunch length,
thereby enhancing the laser gain. Employing this RF harmonic
cavity instabilities are observed with a strong effect on both the
laser radiation properties and the electron beam behaviour. In
this paper, we first present beam characteristics of Super-ACO as
influenced by the harmonic cavity, and the instabilities of the
beam due to this RF cavity. Then we discuss the FEL properties in
presence of the harmonic RF cavity. In general the harmonic cavity
functions as intended, and it is observed that the laser
suppresses the instabilities caused by the harmonic cavity in the
absence of the FEL. 相似文献