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排序方式: 共有151条查询结果,搜索用时 15 毫秒
61.
Quay Lorene C.; Hough Ruth A.; Mathews Marilyn; Jarrett Olga S. 《Canadian Metallurgical Quarterly》1981,17(2):221
Assessed 144 7-, 8-, and 9-yr-olds in lower, middle, and upper socioeconomic status (SES) groups on 4 cognitive variables—classification, class inclusion, conservation of number, and conservation of substance—and on communication encoding effectiveness. It is shown that in addition to age and SES, general cognitive ability accounted for a significant proportion of the variance in communication encoding. (7 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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63.
HH Farrish PH Hsyu JF Pritchard KR Brouwer J Jarrett 《Canadian Metallurgical Quarterly》1994,12(2):265-271
In previous studies we showed that a single implant of polylactic-co-glycolic acid (PLGA) polymer as a film containing isoniazid ensured sustained release of the drug for up to 4 weeks. These studies have been extended to PLGA polymer as a rod which is retrievable. Both types of implant gave therapeutically active levels of free isoniazid in liver and urine for prolonged periods. We assessed the in vivo chemotherapeutic efficacy of the rod implant against heavy infections of virulent Mycobacterium tuberculosis in C57Bl/6 mice. The chemotherapeutic data essentially confirmed the bioavailability data. In one chemotherapeutic study, one (7%) out of 15 mice which received the isoniazid polymer implant died within 30 days of bacterial challenge, while none of those receiving daily oral treatment died. In contrast, 14 (93%) of the 15 control mice died during the same period. In a second study similar results were obtained. 相似文献
64.
M Heitkemper RL Burr M Jarrett V Hertig MK Lustyk EF Bond 《Canadian Metallurgical Quarterly》1998,43(9):2093-2098
Autonomic nervous system function was assessed in women with and without irritable bowel syndrome using frequency domain measures of heart rate variability. Women were interviewed and placed into the irritable bowel syndrome (N = 25) group based on history of diagnosis and self-report of current gastrointestinal symptoms. Women in the control group denied a history of chronic gastrointestinal symptoms (N = 15). Women were followed for one menstrual cycle with a symptom diary, and during mid-luteal phase they wore a Holter 24-hr electrocardiograph monitor. Women with irritable bowel syndrome demonstrated significantly lower vagal tone as measured by the high frequency spectrum relative to control women. In addition, women with irritable bowel syndrome had a flattened 24-hr pattern of heart rate variability, with significantly lower levels of vagal tone during sleep. These results suggest that systemic sympathovagal balance may be shifted in a subset of women with irritable bowel syndrome. 相似文献
65.
Estimating the regression-to-mean effect associated with road accident black spot treatment: towards a more realistic approach 总被引:2,自引:0,他引:2
Until recently, the evaluation of engineering remedial measures at road accident Black Spots was seen as a routine exercise. However, the regression-to mean effect has been found to distort comparisons between before-and-after accident data to a significant extent, and for this and other reasons the problem can no longer be considered as straightforward. Various methods for applying corrections for regression-to-mean have been proposed. They rely on various assumptions about the data which have not been properly investigated or justified. These assumptions relate to the nature of the distribution of mean accident rates between sites, the nature of the population from which the sites are drawn, and the validity of using total accident frequencies as evaluation criteria. The aim of this paper is to investigate the validity of the assumptions, to assess the robustness of the results which are based on them, and to put forward some suggestions for improving the quality of the results. 相似文献
66.
The external surface glycoprotein (SU) of feline leukemia virus (FeLV) contains sites which define the viral subgroup and induce virus-neutralizing antibodies. The subgroup phenotypic determinants have been located to a small variable region, VR1, towards the amino terminus of SU. The sites which function as neutralizing epitopes in vivo are unknown. Recombinant SU proteins were produced by using baculoviruses that contained sequences encoding the SUs of FeLV subgroup A (FeLV-A), FeLV-C, and two chimeric FeLVs (FeLV-215 and FeLV-VC) in which the VR1 domain of FeLV-A had been replaced by the corresponding regions of FeLV-C isolates. The recombinant glycoproteins, designated Bgp70-A, -C, -215, and -VC, respectively, were similar to their wild-type counterparts in several immunoblots and inhibited infection of susceptible cell lines in a subgroup-specific manner. Thus, Bgp70-A interfered with infection by FeLV-A, whereas Bgp70-C, -VC, and -215 did not. Conversely, Bgp70-C, -VC, and -215 blocked infection with FeLV-C, while Bgp70-A had no effect. These results indicate that the site on SU which binds to the FeLV cell surface receptor was preserved in the recombinant glycoproteins. It was also found that the recombinant proteins were able to bind naturally occurring neutralizing antibodies. Bgp70-A, -VC, and -215 interfered with the action of anti-FeLV-A neutralizing antibodies, whereas Bgp70-C did not. Furthermore, Bgp70-C interfered with the action of anti-FeLV-C neutralizing antibodies, while the other proteins did not. These results indicate that the neutralizing epitope(s) of FeLV SU lies outside the subgroup-determining VR1 domain. 相似文献
67.
The observation that changes in bronchial osmolarity can induce bronchoconstriction in asthma inspired the experimental studies which, unexpectedly, revealed that frusemide is an effective bronchoprotective agent against a variety of osmotic and non osmotic stimuli. Although the mechanism of this protective effect is not fully understood, studies in vivo and in vitro suggest that frusemide may inhibit the activation of different cell types induced by bronchoconstrictor stimuli. Other loop diuretics also exert bronchoprotective activity, but frusemide appears to be the more effective bronchoprotective agent of this family, regardless of their diuretic potency and lipid solubility. Despite the relatively large amount of experimental evidence, there is currently little information on the clinical effectiveness of frusemide in asthma and a long-term controlled study is currently in progress. The observations that treatment with a combination of inhaled acetylsalicylate and frusemide results in a markedly increased bronchoprotective effect compared to either drug alone, opens a new perspective in the possible clinical use of these drugs. Preliminary studies suggest that the association of these drugs is well tolerated and may result in a remarkable steroid sparing effect in patients with steroid dependent asthma, for whom a convenient alternative to long-term steroid therapy is not currently available. 相似文献
68.
69.
Controlling Plasmon‐Enhanced Fluorescence via Intersystem Crossing in Photoswitchable Molecules
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Mingsong Wang Gregory Hartmann Zilong Wu Leonardo Scarabelli Bharath Bangalore Rajeeva Jeremy W. Jarrett Evan P. Perillo Andrew K. Dunn Luis M. Liz‐Marzán Gyeong S. Hwang Yuebing Zheng 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(38)
By harnessing photoswitchable intersystem crossing (ISC) in spiropyran (SP) molecules, active control of plasmon‐enhanced fluorescence in the hybrid systems of SP molecules and plasmonic nanostructures is achieved. Specifically, SP‐derived merocyanine (MC) molecules formed by photochemical ring‐opening reaction display efficient ISC due to their zwitterionic character. In contrast, ISC in quinoidal MC molecules formed by thermal ring‐opening reaction is negligible. The high ISC rate can improve fluorescence quantum yield of the plasmon‐modified spontaneous emission, only when the plasmonic electromagnetic field enhancement is sufficiently high. Along this line, extensive photomodulation of fluorescence is demonstrated by switching the ISC in MC molecules at Au nanoparticle aggregates, where strongly enhanced plasmonic hot spots exist. The ISC‐mediated plasmon‐enhanced fluorescence represents a new approach toward controlling the spontaneous emission of fluorophores near plasmonic nanostructures, which expands the applications of active molecular plasmonics in information processing, biosensing, and bioimaging. 相似文献
70.
Navratil P Johnson J Bromm V 《IEEE transactions on visualization and computer graphics》2007,13(6):1712-1718
We describe our visualization process for a particle-based simulation of the formation of the first stars and their impact on cosmic history. The dataset consists of several hundred time-steps of point simulation data, with each time-step containing approximately two million point particles. For each time-step, we interpolate the point data onto a regular grid using a method taken from the radiance estimate of photon mapping. We import the resulting regular grid representation into ParaView, with which we extract isosurfaces across multiple variables. Our images provide insights into the evolution of the early universe, tracing the cosmic transition from an initially homogeneous state to one of increasing complexity. Specifically, our visualizations capture the build-up of regions of ionized gas around the first stars, their evolution, and their complex interactions with the surrounding matter. These observations will guide the upcoming James Webb Space Telescope, the key astronomy mission of the next decade. 相似文献