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61.
Partial 18S rRNA sequences of five chelicerate arthropods plus a
crustacean, myriapod, insect, chordate, echinoderm, annelid, and
platyhelminth were compared. The sequence data were used to infer phylogeny
by using a maximum-parsimony method, an evolutionary-distance method, and
the evolutionary-parsimony method. The phylogenetic inferences generated by
maximum-parsimony and distance methods support both monophyly of the
Arthropoda and monophyly of the Chelicerata within the Arthropoda. These
results are congruent with phylogenies based on rigorous cladistic analyses
of morphological characters. Results support the inclusion of the
Arthropoda within a spiralian or protostome coelomate clade that is the
sister group of a deuterostome clade, refuting the hypothesis that the
arthropods represent the "primitive" sister group of a protostome coelomate
clade. Bootstrap analyses and consideration of all trees within 1% of the
length of the most parsimonious tree suggest that relationships between the
nonchelicerate arthropods and relationships within the chelicerate clade
cannot be reliably inferred with the partial 18S rRNA sequence data. With
the evolutionary-parsimony method, support for monophyly of the Arthropoda
is found in the majority of the combinations analyzed if the coelomates are
used as "outgroups." Monophyly of the Chelicerata is supported in most
combinations assessed. Our analyses also indicate that the
evolutionary-parsimony method, like distance and parsimony, may be biased
by taxa with long branches. We suggest that a previous study's inference of
the Arthropoda as paraphyletic may be the result of (a) having two few
arthropod taxa available for analysis and (b) including long-branched taxa.
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63.
The dynamic response of the fingerpad plays an important role in the tactile sensory response and precision manipulation, as well as in ergonomic design. This paper investigates the dynamic lumped element response of the human fingerpad in vivo to a compressive load. A flat probe indented the fingerpad at a constant velocity, then held a constant position. The resulting force (0-2 N) increased rapidly with indentation then relaxed during the hold phase. A quasilinear viscoelastic model successfully explained the experimental data. The instantaneous elastic response increased exponentially with position, and the reduced relaxation function included three decaying exponentials (with time constants of approximately 4 ms, 70 ms, and 1.4 s) plus a constant. The model was confirmed with data from sinusoidal displacement trajectories. 相似文献
64.
静磁场对单株人体体表正常菌生长影响的研究 总被引:1,自引:0,他引:1
本文通过40mT和120mT两种静磁场作用下表皮葡萄球菌生长过程的研究,发现试验所选强度静磁场加速了表皮葡萄球菌在对数生长期的生长速率,而在进入稳定生长期后其生长速率反而低于对照组,但就整个生长周期而言,静磁场作用下表皮葡萄球菌的总量大于对照组,表明了试验所选静磁场对表皮葡萄球菌生长有一定促进作用. 相似文献
65.
66.
Hanna Pawluk Robert Pawluk Kornelia Kędziora-Kornatowska Józef Kędziora 《Redox report : communications in free radical research》2017,22(6):542-546
Objective: The objective of the present study was to examine selected parameters of the blood redox system in elderly patients with hypertension.examine selected parameters of the blood redox system in elderly patients with hypertension. Methods: We analyzed differences in redox-associated molecules and enzymes among elderly hypertensive subjects (age above 65?years, n?=?49) and two groups of normotensive subjects (<65 years old – Control group I; n?=?27, and >65 – Control group II; n?=?30). Results: Decreased activity of antioxidant enzymes, increased lipid peroxidation and reduced production of nitric oxide were observed in hypertensive subjects, compared to healthy younger controls, or those of the same age. In healthy controls, an age-related decrease in the production of nitric oxide and the activities of SOD-1 and GPx-1 was also evident. The pathology of hypertension was characterised by further, significant decreases in the values of these parameters. When the subgroups of females and males were compared to their respective controls, a compromised redox balance was observed that was more evident in female hypertensives. Discussion: Hypertension in elderly patients is accompanied by changes in biomarkers of antioxidant status and lipid peroxidation status, which significantly differ from those observed in healthy ageing subjects. Our study also suggests that the relationship of gender and changes in redox balance with regard to hypertension should be further explored. 相似文献