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131.
132.
Many plants exude allelochemicals--compounds that affect the growth of neighbouring plants. This study reports further studies of the reported effect of cress (Lepidium sativum) seed(ling) exudates on seedling growth in Amaranthus caudatus and Lactuca sativa. In the presence of live cress seedlings, both species grew longer hypocotyls and shorter roots than cress-free controls. The effects of cress seedlings were allelopathic and not due to competition for resources. Amaranthus seedlings grown in the presence of cress allelochemical(s) had longer, thinner hypocotyls and shorter, thicker roots--effects previously attributed to lepidimoide. The active principle was more abundant in cress seed exudate than in seedling (root) exudates. It was present in non-imbibed seeds and releasable from heat-killed seeds. Release from live seeds was biphasic, starting rapidly but then continuing gradually for 24 h. The active principle was generated by aseptic cress tissue and was not a microbial digestion product or seed-treatment chemical. Crude seed exudate affected hypocotyl and root growth at ~25 and ~450 μg ml(-1) respectively. The exudate slightly (28%) increased epidermal cell number along the length of the Amaranthus hypocotyl but increased total hypocotyl elongation by 129%; it resulted in a 26% smaller hypocotyl circumference but a 55% greater epidermal cell number counted round the circumference. Therefore, the effect of the allelochemical(s) on organ morphology was imposed primarily by regulation of cell expansion, not cell division. It is concluded that cress seeds exude endogenous substances, probably including lepidimoide, that principally regulate cell expansion in receiver plants. 相似文献
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134.
Martin D. Piorkowski Andrew J. Farnsworth Michael Fry Ronald W. Rohrbaugh John W. Fitzpatrick Kenneth V. Rosenberg 《The Journal of wildlife management》2012,76(3):451-456
With upcoming global wind-energy build-out estimated in millions of units, cumulative environmental impacts must be considered and understood to promote responsible expansion of this renewable energy source. In June 2009, 30 wildlife scientists convened in Racine, Wisconsin, USA to identify key research priorities concerning wind energy's potential impacts on migratory wildlife (birds and bats). This working group suggested 4 areas where improved science is most needed to evaluate the impacts of wind-energy development on migrating animals more accurately than can be accomplished today: 1) standardized protocols and definitions; 2) new methods and models for assessing and forecasting risk; 3) documenting lethal and sub-lethal effects at existing wind facilities; and 4) improved facility-site access, data access, and data management for researchers. Focused research based on these priorities will both quantify potential risks associated with wind-energy development and help derive science-based, peer-reviewed, best-management practices for existing and future wind projects. © 2011 The Wildlife Society. 相似文献
135.
Karoli T Mamidyala SK Zuegg J Fry SR Tee EH Bradford TA Madala PK Huang JX Ramu S Butler MS Cooper MA 《Bioorganic & medicinal chemistry letters》2012,22(7):2428-2433
The rise of antibiotic resistance is of great clinical concern. One approach to reducing the development of resistance is to co-administer two or more antibiotics with different modes of action. However, it can be difficult to control the distribution and pharmacokinetics of two drugs to ensure both concentrations remain within the range of therapeutic efficacy whilst avoiding adverse effects. Hybrid drugs, where two drugs are linked together with a flexible linker, have been explored, but the resultant large, flexible molecules can have poor bioavailability. We have developed a chimeric approach using click chemistry where the pharmacophores of two drugs are overlapped into a single smaller, more drug-like molecule. Design and selection of compounds were assisted by in silico structural docking. We prepared a series of compounds that include candidates showing activity against the targets of both trimethoprim; dihydrofolate reductase, and ciprofloxacin; DNA gyrase and topoisomerase IV. The resultant triazole containing molecules show modest, but broad spectrum activities against drug sensitive and resistant Gram-negative and Gram-positive bacteria, with no observable cytotoxicity. 相似文献
136.
The field of personalised or stratified medicine is evolving alongside the formation of a plethora of public/private partnerships and collaborations. These new institutional forms, or 'social technologies', are varied and emerge in response to several drivers, including the need to draw on a broader base of data inputs relating to genomics, patient behaviour and healthcare system differentiation. This paper discusses some of these drivers of partnerships and collaborations. Although the number of such partnerships is growing, their rationale and basis for collaboration remains unclear. Public-private collaborations are at the core of the set of new life sciences policies in the UK but there is little indication in the policy documents of clear boundaries for these partnerships. In part, this is due to the lack of empirical evidence at the system level for conceptualising what is still a relatively new approach. The collection of evidence in the form of broad evaluations, rather than tightly focused theoretical studies, is more likely to be related back to systems and be of more use for formulating policy rationales. 相似文献
137.
I Fry 《Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences》2012,43(3):665-673
This paper challenges the claim that science is metaphysically neutral upheld by contenders of the separation of peacefully co-existent science and religion and by evolutionary theists. True, naturalistic metaphysical claims can neither be refuted nor proved and are thus distinct from empirical hypotheses. However, metaphysical assumptions not only regulate the theoretical and empirical study of nature, but are increasingly supported by the growing empirical body of science. This historically evolving interaction has contributed to the development of a naturalistic worldview that renounces the necessity of a transcendent god and of purposeful design. The thesis presented here differs not only from the claims of the "separatists" and of evolutionary theists. In pointing to the metaphysical aspects of science, I also criticize the failure of some evolutionary naturalists to distinguish between empirical and metaphysical contentions. Most important, based on the examination of science suggested here, creationists' false accusation that science is only a naturalistic dogma is refuted. Finally, the difficulties involved in the position endorsed here for the public support of evolution are acknowledged, taking into account the high religious profile of the American society and the social and political context in the US and in other countries. 相似文献
138.
Andre MJ Fry AC Heyrman MA Hudy A Holt B Roberts C Vardiman JP Gallagher PM 《Journal of strength and conditioning research / National Strength & Conditioning Association》2012,26(3):720-724
Rotational core training is said to be beneficial for rotational power athletes. Currently, there has been no method proposed for the reliable assessment of rotational power. Therefore, our purpose was to determine the test-retest reliability of kinetic and kinematic rotational characteristics of a pulley system when performing a rotational exercise of the axial skeleton in the transverse plane to find out if this would be a reliable tool for evaluating rotational power. Healthy, college-aged men (n = 8) and women (n = 15) reported for 3 testing sessions. The participants were seated on a box, and they held the handle with both arms extended in front of their body, starting their motion with their torso rotated toward the machine. All the participants rotated their torso forcefully until they reached 180° of rotation, and they then slowly returned to the starting position, 3 times per trial, with 3 loads: 9% body weight (BW), 12% BW, and 15% BW. The repetition with the greatest power for each trial for each load was analyzed. The mean peak power repetition (watts) for all the subjects was 20.09 ± 7.16 (9% BW), 26.17 ± 8.6 (12% BW), and 30.74 ± 11.022 (15% BW) in the first training session and 22.3 ± 8.087 (9% BW), 28.7 ± 11.295 (12% BW), and 33.52 ± 12.965 (15% BW) in the second training session with intraclass correlation coefficients of 0.97 (9%BW), 0.94 (12%BW), and 0.95 (15%BW). When the participants were separated by sex, there were no significant differences between groups. Based on these results, it was found that a pulley system and an external dynamometer can be used together as a reliable research tool to assess rotational power. 相似文献
139.
Nusrat Homaira Stephen P. Luby William A. Petri Raija Vainionpaa Mustafizur Rahman Kamal Hossain Cynthia B. Snider Mahmudur Rahman A. S. M. Alamgir Farzina Zesmin Masud Alam Emily S. Gurley Rashid Uz Zaman Tasnim Azim Dean D. Erdman Alicia M. Fry Joseph Bresee Marc-Alain Widdowson Rashidul Haque Eduardo Azziz-Baumgartner 《PloS one》2012,7(2)
140.
The deep subseafloor biosphere supports a diverse population of prokaryotes belonging to the Bacteria and Archaea. Most of the taxonomic groups identified by molecular methods contain mainly uncultured phylotypes. Despite this several cultured strains have been isolated from this habitat, but they probably do not represent the majority of the population. Evidence is starting to suggest that some of the activities measured, such as sulphate reduction and methanogenesis, reflected in geochemical profiles, are carried out by a small subset of the community detected by molecular methods. It is further possible that heterotrophy may be the most important mode of metabolism in subsurface sediments and heterotrophic microorganisms could dominate the uncultured prokaryotic population. Although, heterotrophy is limited by the increasing recalcitrance of organic matter with depth, this may be counteracted by thermal activation of buried organic matter providing additional substrates at depth. 相似文献