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961.
To clarify the causal relationship between spontaneous recanalization of the occluded cerebral artery and development of hemorrhagic infarction, 15 patients with internal carotid or middle cerebral arterial axis occlusion were submitted to consecutive lumbar punctures and follow-up cerebral angiography. Consequently, six of seven recanalized patients had sanguineous cerebrospinal fluid (CSF) on the second or third day after ictus, while only one of eight non-recanalized patients had bloody CSF. It was strongly suggested that recanalization might have an initimate relationship with the development of hemorrhagic infarction. 相似文献
962.
Vitamin E deficiency was found to stimulate FMLP (N-formyl-L-methionyl-L-leucyl-L-phenylalanine)-induced biosynthesis of PAF
(1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine) in polymorphonuclear leucocytes (PMN) from rat peritoneum. In three separate experiments each,
the amounts of PAF synthesized during 6min and 12 min incubation of PMN cells from control, vitamin E-supplemented, and vitamin
E-deficient rats were 129–240, 131–227 and 248–354 pmol/106 cells, respectively. The activity of the acetyl-transferase, which transfers the acetyl moiety of [3H]acetyl-CoA to 2-lysoPAF (1-O-alkyl-sn-glycero-3-phosphocholine) to form [3H]PAF, was higher in PMN homogenates from vitamin E-deficient rats (2.28±0.07 nmol/min/mg protein) than in those from E-supplemented
rats (1.06±0.10 nmol/min/mg protein). However, there was no difference between the two groups in the activity of acetylhydrolase
(4.26±0.71 and 4.26±0.06 nmol/min/mg protein, respectively), measured as degradation of [3H]PAF to [3H]lysoPAF.In vitro addition of α-tocopherol did not inhibit the increased activity of acetyl-transferase in vitamin E-deficient rats, in-dicating
that the enzyme in vitamin E-supplemented rats was not directly inhibited by α-tocopherol. The acetyltransferases of the two
groups showed similar Km values for acetyl-CoA, but different Vmax values (225 μM and 6.4 nmol/min/mg protein in vitamin E-deficient
rats, and 216 μM and 3.6 nmol/min/mg protein in vitamin E-supplemented rats), suggesting that the enzyme was not activated
but increased in amount in vitamin E deficiency. 相似文献
963.
Toshinobu Yogo Koichi Kikuta Yasuhiro Ito Shin-ichi Hirano 《Journal of the American Ceramic Society》1995,78(8):2175-2179
Highly oriented K(Ta,Nb)O3 (Ta:Nb = 65:35) (KTN) thin films of perovskite structure were synthesized successfully on Pt(100)/MgO(100) substrates from a metal alkoxide solution through reaction control. Homogeneous KTN coating solutions prepared from KOC2 H5 , Ta(OC2 H5 )5 , and Nb(OC2 H5 )5 in ethanol were analyzed by 1 H, 13 C, and 93 Nb NMR spectroscopy. The KTN precursor included a molecular-level mixture of K[M(OC2 H5 )6 ] (M = Ta, Nb) units interacting in ethanol solution. X-ray pole figure measurement showed that perovskite KTN films crystallized on Pt(100)/MgO(100) substrates had not only a (100) orientation but also a three-dimensional regularity of grains. The remanent polarization and coercive field of the KTN film (thickness, 1.0 μm) crystallized at 700°C were 1.5 μC/cm2 and 8.7 kV/cm, respectively, at 225 K. 相似文献
964.
965.
Reviews rat experiments using aversive stimuli in which some element of uncertainty was involved. Nine cases of conditions that produce uncertainty are described, and relevant experimental facts are examined. Rats were found to prefer situations involving certainty to those involving uncertainty, and the rats' basal rate of responding was found to be less in suppression situations involving uncertainty about aversive environmental events than in those involving relative certainty. Results are obtained when the aversive stimuli the rats received were physically matched in quantity among the conditions compared. Results are discussed with reference to the safety signal, preparatory response, time allocation, contextual fear, and information hypotheses. It is concluded that the function of the concept of uncertainty is to organize a class of studies that are otherwise unrelated. (59 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
966.
Molybdenum hexacarbonyl entrapped in NaY zeolite was oxidized with molecular oxygen by UV-irradiation at room temperature or by thermal treatment at 343–373 K. Both oxidation procedures resulted in the identical molybdenum(VI) oxide; molybdenum dimer species (Mo-Mo distance: 0.321 nm). The Mo-Mo bonding of the oxide species was degraded on an evacuation at 673 K, while it was considerably stable in the presence of gaseous oxygen. 相似文献
967.
The effect of neutron irradiation on twinning deformation is investigated at 77 K using unirradiated and to a fluence of 4.1 × 1019n/cm2 irradiated zirconium. The slip line density Ns, the twin volume fraction Vt and the twin density Nt for both specimens were determined as a function of strain by means of optical microscopy. The twins were determined using the diffraction profiles of {101̄2} twins at the early stages, as well as, {112̄2} and {112̄4} twins at the latter stages of deformation. It is shown that the nucleation of twins was affected more strongly than the growth by neutron irradiation. 相似文献
968.
Yasuhiro Awakura Akito Uno Hiroshi Majima 《Metallurgical and Materials Transactions B》1989,20(1):110-112
formerly Graduate Student, Department of Metallurgy, Kyoto University, Japan 相似文献
969.