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51.
EG Ciolac SS Mantuani CM Neiva CEL Verardi DM Pess?a-Filho L Pimenta 《Biology of sport / Institute of Sport》2015,32(2):103-108
The aim of the present study was to analyse the usefulness of the 6-20 rating of perceived exertion (RPE) scale for prescribing and self-regulating high-intensity interval training (HIT) in young individuals. Eight healthy young subjects (age = 27.5±6.7 years) performed maximal graded exercise testing to determine their maximal and reserve heart rate (HR). Subjects then performed two HIT sessions (20 min on a treadmill) prescribed and regulated by their HR (HR: 1 min at 50% alternated with 1 min at 85% of reserve HR) or RPE (RPE: 1 minute at the 9-11 level [very light-fairly light] alternated with 1 minute at the 15-17 level [hard-very hard]) in random order. HR response and walking/running speed during the 20 min of exercise were compared between sessions. No significant difference between sessions was observed in HR during low- (HR: 135±15 bpm; RPE: 138±20 bpm) and high-intensity intervals (HR: 168±15 bpm; RPE: 170±18 bpm). Walking/running speed during low- (HR: 5.7±1.2 km · h−1; RPE: 5.7±1.3 km · h−1) and high-intensity intervals (HR: 7.8±1.9 km · h−1; RPE: 8.2±1.7 km · h−1) was also not different between sessions. No significant differences were observed in HR response and walking/running speed between HIT sessions prescribed and regulated by HR or RPE. This finding suggests that the 6-20 RPE scale may be a useful tool for prescribing and self-regulating HIT in young subjects. 相似文献
52.
Scanning and transmission electron microscopy revealed that intrathoracically-inoculated microfilariae (mff) of Dirofilaria immitis elicited a rapid and effective immune response in the hemocoel of Aedes trivittatus mosquitoes. Hemocyte lysis and melanization of inoculated mff began immediately following exposure to the hemolymph environment. Initial melanin accumulation occurred at any site along the surface of mff and rapidly increased in thickness. Hemocyte encapsulation generally described for insects did not occur, but hemocytes might be necessary for activation of the melanization response. Although intact hemocytes were never abundant, those that were present seemed to show an active secretion of membrane-bound vacuoles directed toward mff. Activated hemocytes were in close association, but never in direct contact with the parasite, and were most commonly seen in various stages of lysis. Numerous cell remnants were noted throughout the developing melanin capsule. Parasites were completely melanized by 24 hr postinoculation (PI). By about 3 days PI, a membrane began to form around deposited melanin and hemocyte remnants. This developed into a double membrane-like structure of 25-30 nm thickness and resulted in the enclosure and isolation of the mff, melanin deposits, and cellular remnants from hemolymph components. It is suggested that this membrane functions as a boundary to isolate the melanized parasite and prevents additional hemocyte involvement. 相似文献
53.
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.
相似文献
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55.
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
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57.
The melanization response of Aedes trivittatus and A. aegypti (black-eyed Liverpool strain) against intrathoracically inoculated sheathed and chemically exsheathed Brugia pahangi microfilariae (mff) was assessed daily through 5 days postinoculation (PI). Response of A. aegypti against exsheathed mff was significantly reduced on all days compared with the response against sheathed mff, and a significantly greater percentage of exsheathed mff were alive through 4 days PI than were sheathed mff. The melanization response of A. trivittatus was nearly 100% effective against either sheathed or exsheathed mff by Day 2 PI. When mff were allowed to migrate through A. aegypti midguts in vitro before inoculation into intact A. aegypti, nearly 94% () of the parasites recovered had avoided the response and were developing. Penetration of A. trivittatus midguts in vitro by mff before inoculation into intact A. trivittatus did not prevent a melanization response. Inoculation of mff into A. trivittatus following A. aegypti midgut penetration, however, resulted in almost 60% () of the mff avoiding the response and developing as normal L1 larvae after 5 days PI. The possibility of mff acquiring host antigens during midgut penetration and therefore avoiding recognition as nonself by mosquitoes, and (or) the possibility of the midgut environment modifying or stimulating mff to inhibit the response of mosquitoes are discussed. 相似文献