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51.
Jarbe Tjorbjorn U. C.; Falk Ulla; Mohammed Abdul L.; Archer Trevor 《Canadian Metallurgical Quarterly》1988,102(6):925
Assessed the role of noradrenaline (NA) on the acquisition of an aversively motivated discrimination task and its reversal. A conditioned taste aversion procedure was used. NA depletions were achieved through 2 pharmacological means: systemic N-2 chloroethyl-N-ethyl-2-bromo-benzylamine (DSP4) and destruction of the dorsal noradrenergic bundle (DNAB) with 6-hydroxydopamine (6-OHDA). Both procedures caused marked reductions of NA in the frontal cortex and hippocampus. In neither of the studies (Exp 1, DSP4 and Exp 2, DNAB) were there any significant changes between controls and NA-depleted rats in either the rate of acquisition of the original discrimination (Phase 1) or the subsequent reversal (Phase 2). This occurred irrespective of which of the 2 stimuli (a taste cue or a tongue-tactile cue) initially was used as the conditioned stimulus/stimuli (CS) (the stimulus first followed by contingent administration of lithium chloride and later, by saline injections). Thus NA does not appear to be critically involved in the acquisition and reversal of a taste/tactile discrimination task. The significance of forebrain NA for other discrimination tasks is discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
52.
该文评述了应用酶放大电极的免疫测定法的进展,从原理和应用两方面进行了探讨.着重介绍了作者所在实验室在90年代以来的相关工作. 相似文献
53.
Summary: Propylene was copolymerized with 10‐undecen‐1‐ol using dimethylsilanylbis(2‐methyl‐4‐phenyl‐1‐indenyl)zirconium dichloride as catalyst and MAO and TIBA as cocatalysts. Comonomer incorporations from 0.1 to 0.9 mol‐% (0.5 to 3.6 wt.‐%) were obtained. These hydroxyl functionalized copolymers were applied as compatibilizers to PP/PA6 blend with a composition of 70/30. For comparison, hydroxyl functionalized polyethylene prepared with metallocene catalyst and commercial MAH grafted ethylene butyl acrylate (E/BA/MAH) and poly(propylene) (PP‐g‐MAH) were also used as compatibilizers. Effects of the compatibilizers on morphology and mechanical and thermal properties of the blends were studied. Enhanced adhesion between the blend components was observed in morphology and dynamic mechanical studies. Although improvement in toughness was not as pronounced as expected, there were indications that the hydroxyl functionalized propylene copolymers prepared with metallocene catalysts could serve as a new type of compatibilizer in polymer blends.
54.
Anne T Saber Nicklas R Jacobsen Jette Bornholdt Sanna L Kjær Marianne Dybdahl Lotte Risom Steffen Loft Ulla Vogel Håkan Wallin 《Particle and fibre toxicology》2006,3(1):4-8
Background
Particulate air pollution has been associated with lung and cardiovascular disease, for which lung inflammation may be a driving mechanism. The pro-inflammatory cytokine, tumor necrosis factor (TNF) has been suggested to have a key-role in particle-induced inflammation. 相似文献55.
Anne Steen-Hansen Ragni Fjellgaard Mikalsen Ulla Eidissen Jensen 《Fire Technology》2018,54(6):1585-1608
A bench-scale experimental setup has been used to study the conditions necessary for smouldering ignition in four types of loose-fill wood fibre thermal insulation, and to study the development of the smouldering process. The products varied with regard to wood species, grain size and fire retardant chemical additives. The test material was placed in an insulated open top container and heated from below. Temperatures within the sample and mass loss were measured during the tests. Both the fibre size and the level of added fire retardant seem to influence the smouldering ignition. Two different types of smouldering were identified in this study. Materials undergoing smouldering Type 1 obtained maximum temperatures in the range 380°C to 440°C and a total mass loss of 40 wt% to 50 wt%. Materials undergoing smouldering Type 2 obtained maximum temperatures in the range 660°C to 700°C and a total mass loss of 80 wt% to 90 wt%. This implies that Type 2 smouldering involves secondary char oxidation, which represents a risk for transition to flaming combustion and thereby a considerable fire hazard. This has been an exploratory project and the results must therefore be considered as indicative. The findings may, however, have implications for fire safety in the practical use of loose-fill wood fibre insulation in buildings, and further experimental studies should be performed with this in mind to obtain more knowledge about the topic. 相似文献
56.
M?kikangas Anne; Feldt Taru; Kinnunen Ulla; Tolvanen Asko; Kinnunen Marja-Liisa; Pulkkinen Lea 《Canadian Metallurgical Quarterly》2006,18(4):444
This study provides new knowledge about the factor structure of the 12-item General Health Questionnaire (GHQ-12; D. Goldberg, 1972) through the application of confirmatory factor analysis to longitudinal data, thereby enabling investigation of the factor structure, its invariance across time, and the rank-order stability of the factors. Two community-based longitudinal adult samples with 1-year (n = 640) and 6-year (n = 330) follow-up times were studied. As a result, the correlated 3-factor model (i.e., Anxiety/Depression, Social Dysfunction, and Loss of Confidence) showed a better fit with both samples than the alternative models. The correlated 3-factor structure was also relatively invariant across time in both samples, indicating that the scale has good construct validity. The rank-order stabilities of the factors were low across time, which suggests that the GHQ-12 measures temporal mental state. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
57.
V. G. Milt R. Spretz M. A. Ulla E. A. Lombardo J. L. García Fierro 《Catalysis Letters》1996,42(1-2):57-63
Highly crystalline, monophasic LaFeO3 and LaCoO3 perovskites, prepared by the explosion method, are shown to be heterogeneous at surface level. The outmost atomic layers of these perovskites contain high concentrations of carbonate-type species. Their specific activities for methane combustion are in fact identical to La2O2CO3 and air-exposed La2O3. These results compared with pertinent data from the literature hint that surface heterogeneity may be often present in mixed oxides catalysts. 相似文献
58.
59.
Rachel I. Adams Hanna Leppänen Anne M. Karvonen José Jacobs Alicia Borràs-Santos Maria Valkonen Esmeralda Krop Ulla Haverinen-Shaughnessy Kati Huttunen Jan-Paul Zock Anne Hyvärinen Dick Heederik Juha Pekkanen Martin Täubel 《Indoor air》2021,31(6):1952-1966
Moisture-damaged buildings are associated with respiratory symptoms and underlying diseases among building occupants, but the causative agent(s) remain a mystery. We first identified specific fungal and bacterial taxa in classrooms with moisture damage in Finnish and Dutch primary schools. We then investigated associations of the identified moisture damage indicators with respiratory symptoms in more than 2700 students. Finally, we explored whether exposure to specific taxa within the indoor microbiota may explain the association between moisture damage and respiratory health. Schools were assessed for moisture damage through detailed inspections, and the microbial composition of settled dust in electrostatic dustfall collectors was determined using marker-gene analysis. In Finland, there were several positive associations between particular microbial indicators (diversity, richness, individual taxa) and a respiratory symptom score, while in the Netherlands, the associations tended to be mostly inverse and statistically non-significant. In Finland, abundance of the Sphingomonas bacterial genus and endotoxin levels partially explained the associations between moisture damage and symptom score. A few microbial taxa explained part of the associations with health, but overall, the observed associations between damage-associated individual taxa and respiratory health were limited. 相似文献
60.
Catalytic combustion of diesel soot on Co, K supported catalysts 总被引:8,自引:0,他引:8
Catalysts containing 12% Co and 4.5% K, supported on MgO and CeO2 have been studied for diesel soot catalytic combustion. It has been found that this reaction occurs by a redox mechanism when Co and K are deposited on any of the above-mentioned supports. On MgO-supported catalysts, CoOx species are responsible for the supply of oxygen by a redox reaction. In this catalyst, K plays different roles, one of them being the stabilization of the CoOx particles. On CeO2-supported catalysts, Co does not significantly improve the activity of the K/CeO2 catalyst, since in this case the support itself displays redox properties. XPS analyses indicate that the oxygen availability on the surface is much higher on CeO2 than on MgO. On both CeO2 and MgO-supported catalysts, K might provide a route for CO2 release through a carbonate intermediate species. The presence of NO in the gas phase improves the catalytic activity for soot elimination. NO is oxidized to NO2 on the Co, K/CeO2 catalyst, and NO2 is a stronger oxidizing agent than O2, therefore decreasing the temperature needed to burn the soot. 相似文献