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71.
Abstract— Pre-treatment of rat brain slices with organic mercurials prevents the increased acetylcholine release induced by tityustoxin. This inhibition is reversed by dithiothreitol. N-Ethylmaleimide blocks the tityustoxin effect irreversibly. Simultaneous incubation with mercurials and toxin reveals a competition of both ligands for a membrane sulfhydryl group apparently required for tityustoxin activity. 相似文献
72.
Antônio A. Lins Mesquita Wanderley Gonçlves De Oliveira Rosa M. Taveira Neiva Otto R. Gottlieb 《Phytochemistry》1975,14(3):803-806
The wood of Tovomita pyrifolium (Guttiferae) contains the novel tovopyrifolins A [1,6-dihydroxy-7-methoxy-5-prenyl-6′,6′-dimethylpyrano (2′,3′:3,2)xanthone], B (1,5-dihydroxy-3,4-dimethoxyxanthone) and C (1,3,5-trihydroxy-2-methoxyxanthone) and also the known tovophyllins A and B [structure revised to 1,6-dihydroxy-5-prenyl-6′, 6′-dimethylpyrano(2′,3′:3,2)-6″,6″-dimethylpyrano(2″,3″:7,8)xanthone]. 相似文献
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Filipe Manuel Clemente Rodrigo Ramirez-Campillo Daniel Castillo Javier Raya-Gonzlez Markel Rico-Gonzlez Rafael Oliveira Thomas Rosemann Beat Knechtle 《Biology of sport / Institute of Sport》2022,39(3):765
Plyometric jump training (PJT) can be used for improving balance through bilateral and unilateral jump-landing drills. Since the increased number of articles testing the effects of PJT on dynamic and static balance, it is relevant to summarize the evidence and determine the effects across different original articles. This systematic review with meta-analysis was conducted to assess the effects of PJT programs on dynamic and static balance in soccer players. The data sources utilized were Cochrane, Medline (PubMed), SPORTDiscus, and Web of Science. (i) Soccer players of any age or sex without injury, illness, or other clinical conditions; (ii) PJT-based programs restricted to a minimum of three weeks (duration); (iii) passive or active control groups; (iv) pre-post interventions values of dynamic and/or static balance; (v) randomized-controlled trials; and (vi) peerreviewed original full-text studies written in English, Portuguese, and/or Spanish. The database search initially identified 803 titles. From those, eight articles were eligible for the systematic review and meta-analysis. The results showed no significant differences between PJT and active controls in dynamic anterior, postero-medial, or postero-lateral balance for both left and right legs (p > 0.05). Additionally, no significant differences were found between PJT and active controls in terms of static balance (p = 0.495). The current evidence suggests that PJT has no significant advantage over active control groups in terms of dynamic or static balance. 相似文献
76.
Luciano?da Rocha?Corrêa Daniel?Cristiano?Paim Joséli?Schwambach Arthur?Germano?Fett-NetoEmail author 《Plant Growth Regulation》2005,45(1):63-73
Comparisons between related species with different rooting capacities can provide insights into the mechanisms controlling adventitious root development. The availability of carbohydrates is often considered exclusively as an energetic requirement to drive root development; the major regulatory role in the process is often attributed to phytohormones, particularly auxin. The roles of light quantity (irradiance) and carbohydrate supply available to young aseptic donor-plants on the adventitious rooting response of Eucalyptus globulus (rooting recalcitrant) and Eucalyptus saligna (easy-to-root) were examined. The effects of the type of carbohydrate supply (sucrose or glucose) on the rooting response of cuttings was also evaluated. Light intensity supplied to mother-plants (30 or 60 mol m–2 s–1) had limited influence on the rooting response of both species, whereas dark periods were detrimental, particularly for E. globulus. In E. globulus, rooting was promoted by the absence of sucrose in donor-plant media. Presence of sucrose in donor plant medium promoted root number but did not affect rooting percentage of E. saligna. A positive effect of glucose on cutting rhizogenesis was found if this hexose was supplied during the root induction phase, followed by sucrose in the root formation step, especially for E. globulus. The same effect was not seen with fructose. The beneficial effect of glucose in the induction phase on root number was also evident under suboptimal auxin concentrations. 相似文献
77.
Tadeu Siqueira Luis Mauricio Bini Fabio Oliveira Roque Sheyla Regina Marques Couceiro Susana Trivinho‐Strixino Karl Cottenie 《Ecography》2012,35(2):183-192
Ecologists have long investigated why communities are composed of a few common species and many rare species. Most studies relate rarity to either niche differentiation among species or spatial processes. There is a parallel between these processes and the processes proposed to explain the structure of metacommunities. Based on a metacommunity perspective and on data on stream macroinvertebrates from different regions of Brazil, we answer two questions. 1) Are sets of common and rare species affected by similar niche and spatial processes? 2) How does the community composition of common and of rare species differ? The main hypothesis we test is that common species are mainly affected by environmental factors, whereas rare species are mostly influenced by dispersal limitation. We used variation partitioning to determine the proportion of variation explained by the environment and space in common and rare species matrices. Contrary to our expectations, evidence supported the idea that both common and rare species are affected mainly by environmental factors, even after controlling for the differing information content between common and rare species matrices. Moreover, the abundance of some common species is also a good predictor of variation in rare species matrices. Niche differences are unlikely to be the sole cause of patterns of rarity in these metacommunities. We suggest that sets of common and rare species react to similar major environmental gradients and that rare species also respond to processes that operate at a more fine‐grained spatial scale, particularly biotic interactions. We extend the view that species sorting is the dominant process structuring metacommunities and argue that future studies focusing on rarity would benefit from a metacommunity perspective. 相似文献
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Ana Luiza Menegatti Pavan Maria Eugênia Dela Rosa Guilherme Giacomini Fernando Antonio Bacchim Neto Seizo Yamashita Luiz Carlos Vulcano Sergio Barbosa Duarte José Ricardo de Arruda Miranda Diana Rodrigues de Pina 《PloS one》2016,11(4)
Digital radiographic imaging is increasing in veterinary practice. The use of radiation demands responsibility to maintain high image quality. Low doses are necessary because workers are requested to restrain the animal. Optimizing digital systems is necessary to avoid unnecessary exposure, causing the phenomenon known as dose creep. Homogeneous phantoms are widely used to optimize image quality and dose. We developed an automatic computational methodology to classify and quantify tissues (i.e., lung tissue, adipose tissue, muscle tissue, and bone) in canine chest computed tomography exams. The thickness of each tissue was converted to simulator materials (i.e., Lucite, aluminum, and air). Dogs were separated into groups of 20 animals each according to weight. Mean weights were 6.5 ± 2.0 kg, 15.0 ± 5.0 kg, 32.0 ± 5.5 kg, and 50.0 ± 12.0 kg, for the small, medium, large, and giant groups, respectively. The one-way analysis of variance revealed significant differences in all simulator material thicknesses (p < 0.05) quantified between groups. As a result, four phantoms were constructed for dorsoventral and lateral views. In conclusion, the present methodology allows the development of phantoms of the canine chest and possibly other body regions and/or animals. The proposed phantom is a practical tool that may be employed in future work to optimize veterinary X-ray procedures. 相似文献
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