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51.
52.
This paper presents two examples of how impedance cardiography may be used to interpret the hemodynamic influences on blood pressures measured during behavioral stress. In Study 1, blood pressure changes which were similar during two tasks were shown to have important differences in their cardiac output and vascular resistance components. During work on a reaction time task having aversive incentives compared with a neutral task, the blood pressure changes were seen to be associated with lowered vascular resistance and raised cardiac activity, a "fight-flight" pattern. In Study 2, blood pressure response differences between two subject groups working on an identical task were found to have blood pressure changes differing in their underlying cardiac and vascular components as measured by impedance. Such uses impedance cardiography have widespread potential application in psychophysiological research with humans. 相似文献
53.
This article presents the properties of animation with space-time objects. A space-time object means here a geometrical object embedded in R4 with a volumic topology. Resulting animations are obtained by deforming space-time objects with a free-form deformation model. In this way topological modifications, such as disconnecting or hole making, as well as classical geometrical modifications, can be created in an animated object. 相似文献
54.
用动态剪切模量估算NR与SBR硫化胶的化学交联密度 总被引:2,自引:2,他引:2
用美国Monsanto公司的橡胶加工过程分析仪测定NR和SBR硫化胶或混炼胶料的动态剪切模量(G'),进而根据G_N ̄0=g×2X_0RT和Ge=g'×2X_(ph)RT估算其硫化胶的化学交联密度(X_ch),结果发现:NR/过氧化二异丙苯体系硫化胶和混炼胶料的G'是不同的,但用G'估算的X_ch与用化学分析法测定的结果基本相近;对SBR/促进剂TMTD体系,用这种方法估算的X_(ch)接近用应力-应变法和NMR法的估算值;对NR/促进剂TMTM体系,用G'估算的X_(ch)与用溶胀法获得的数据基本接近。用G'估算X_(ch)法,十分简单、方便。 相似文献
55.
56.
A. Aubert J.P. Rebrassé L. Dantas de Morais N. Labat H. Frémont 《Microelectronics Reliability》2010,50(9-11):1688-1691
Because of its advantages (reduction of thickness, improvement of the signal delay and of the thermal dissipation…), Cu/low-k technologies are more and more used for RF applications in semiconductor industry. The failure analysis of such devices becomes a new challenge. This paper deals with a failure analysis case study on copper and low-k dielectric structure encapsulated in a plastic package. It shows the limitations of the techniques used in a standard failure analysis flow and presents a new sample preparation combining laser package ablation and specific RIE process for front-side decapsulation. This innovative sample preparation flow has been found mandatory for solving the failure analysis case: it was demonstrated that there was not any defect at the surface of the die and this method enabled the access to an EOS defect located between two metal layers. 相似文献
57.
G Perini MF Saettone M Carafa E Santucci F Alhaique 《Canadian Metallurgical Quarterly》1996,135(2):145-146
This report provides X-ray diffraction and Raman spectral evidence that, when 2,6-dichlorobenzonitrile is present in the culture medium, Acetobacter xylinum, which is a model system for investigation of the biosynthesis of native cellulose, produces cellulose II, as well as cellulose I. The significance of the observations with respect to the mechanism of biosynthesis of cellulose is discussed briefly. 相似文献
58.
DL Smalley JJ Levine DR Shanklin MF Hall MV Stevens 《Canadian Metallurgical Quarterly》1996,196(5):567-574
The current study evaluated immune response to silicon dioxide in children born to women with silicone breast implants. In part one of the study, the T lymphocytes of 21 of 24 such children were significantly stimulated by silicon dioxide (silica). Part two consisted of eleven children, four born preimplantation and seven born postimplantation. None of the preimplant offspring showed T cell responses to silica; five of the seven postimplant children were positive for T cell memory for silica. Part three was a blinded study based on statistically significant differences in T cell stimulation with silicon dioxide between postimplant children and controls. These findings indicate a common immune reaction, that of T cell memory, occurs in mothers and their children born after exposure to silicone mammary implants placed prior to pregnancy. Since not all such children were breast fed the result favors transplacental passage of immunogens such as silicone oligomers or through maternofetal cellular traffic. 相似文献
59.
A man, 23 years of age, had a typical erythema infectiosum, complicated by a severe bilateral brachial plexus neuritis. Motor function recovered slowly and only partially after 6 months. An infection by human parvovirus B19 was demonstrated, with strongly positive and gradually declining IgM antibodies and viral DNA detectable in serum for more than 3 months. There was also clear evidence of a recent infection by cytomegalovirus. The interaction between these two viruses could be responsible for this rare and severe complication of common infections in this patient. 相似文献
60.
M Peng T Abribat E Calvo D LeBel MF Palin G Bernatchez J Morisset G Pelletier 《Canadian Metallurgical Quarterly》1998,76(4):1178-1188
We examined the ontogeny of mRNA levels of IGF-I and -II, IGF type 1 (IGFI-R) and type II receptors (IGFII-R), IGF binding protein-1 and -3 (IGFBP-1 and -3), GH receptor (GHR), and tissue concentrations of IGF and IGFBP in the pancreas of pigs. Tissues were collected from fetuses at 90 and 110 d of gestation and from pigs at 1, 21, 90 and 180 d of age. Northern blots were performed using total RNA hybridized with 32P-labeled cDNA probes (human IGF-I and human IGFI-R) and cRNA probes (rat IGF-II, human IGFII-R, human IGFBP-1, pig IGFBP-3, and pig GHR). There were two accelerated growth stages of the pancreas: the first one at 90 d of fetal life, which is characterized by cell hyperplasia (high ratio of DNA to body weight), and the second one at postnatal 90 d, which is attributed to cell hypertrophy (high ratios of pancreatic weight, RNA, and protein to DNA). The level of IGF-II mRNA and its tissue concentration were predominant during fetal life and low thereafter. The IGF-I mRNA level was high during fetal and early postnatal life and decreased thereafter. Messenger RNA levels of IGFI-R, IGFBP-3, and GHR and concentrations of IGFBP-1 and -2 were abundant during fetal and early postnatal life. In conclusion, IGF may be involved in various physiological periods of pancreatic development in pigs. 相似文献