共查询到20条相似文献,搜索用时 31 毫秒
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Pin-xian Xi Liang Huang Heng Liu Peng-fei Jia Feng-juan Chen Min Xu Zheng-zhi Zeng 《Journal of biological inorganic chemistry》2009,14(6):815-819
Abstract The synthesis and spectral properties of a chemidosimeter 1,4-di[2-(6-ethylamino-3-ethylimino-2,7-dimethyl-3H-xanthen-9-yl)
benzoic acid (aminomethyl)-3-phenylthiourea] benzene (1) for Hg(II) ions are reported, and it has been demonstrated that 1 can be used as a fluorescent probe for monitoring Hg(II) ions in living cells.
Graphical abstract A highly sensitive fluorescent probe (1) was developed as a fluorescent and colorimetric chemodosimeter in dimethyl sulfoxide/methanol solution with a broad pH range
(pH 5–10) and high selectivity toward Hg2+ ions but no significant response toward other competitive cations. Furthermore, by means of confocal laser scanning microscopy
experiments, it is demonstrated that 1 can be used as a fluorescent probe for monitoring Hg2+ in living cells.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
相似文献
Zheng-zhi ZengEmail: |
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The Cauchy problem for one-dimensional spiking neuron models 总被引:1,自引:1,他引:0
Romain Brette 《Cognitive neurodynamics》2008,2(1):21-27
I consider spiking neuron models defined by a one-dimensional differential equation and a reset—i.e., neuron models of the
integrate-and-fire type. I address the question of the existence and uniqueness of a solution on for a given initial condition. It turns out that the reset introduces a countable and ordered set of backward solutions for
a given initial condition. I discuss the implications of these mathematical results in terms of neural coding and spike timing
precision.
相似文献
Romain BretteEmail: |
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Sub-Antarctic Marion Island has had a permanent research station for 50 years and the islands Wandering Albatrosses have been intensively studied for 20 years. The reactions of breeding birds to approaches by a human on foot were recorded. Three response variables were calculated: intensity of vocal reaction (IVR), intensity of non-vocal reaction (INR) and overall response index (ORI). At 5 m from the nest, twice as many birds stood and/or vocalised as at 15 m. Nearest neighbour distance, age and gender did not explain individual variability of responses. Study colony birds had higher IVR scores than non-study colony birds; birds at colonies closest to the station had the highest ORI scores. A better breeding record was associated with lower IVR and ORI scores, but a causative relationship remains to be demonstrated. A minimum viewing distance of 25 m is recommended for breeding Wandering Albatrosses.
相似文献
Marienne S. de VilliersEmail: Fax: +27-21-6503434 |
John CooperEmail: |
Peter G. RyanEmail: |
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The recent contribution by Jarmila Kukalová-Peck on Hennigian phylogenetics and hexapod limb evolution is critically evaluated.
相似文献
Michael S. Engel (Corresponding author)Email: |
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A key point in the analysis of dynamical models of biological systems is to handle systems of relatively high dimensions.
In the present paper we propose a method to hierarchically organize a certain type of piecewise affine (PWA) differential
systems. This specific class of systems has been extensively studied for the past few years, as it provides a good framework
to model gene regulatory networks. The method, shown on several examples, allows a qualitative analysis of the asymptotic
behavior of a PWA system, decomposing it into several smaller subsystems. This technique, based on the well-known strongly
connected components decomposition, is not new. However, its adaptation to the non-smooth PWA differential equations turns
out to be quite relevant because of the strong discrete structure underlying these equations. Its biological relevance is
shown on a 7-dimensional PWA system modeling the gene network responsible for the carbon starvation response in Escherichia coli.
相似文献
Laurent Tournier (Corresponding author)Email: |
Jean-Luc GouzéEmail: |
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Peter Godfrey-Smith 《Biology & philosophy》2007,22(3):429-437
Jablonka and Lamb's claim that evolutionary biology is undergoing a ‘revolution’ is queried. But the very concept of revolutionary
change has uncertain application to a field organized in the manner of contemporary biology. The explanatory primacy of sequence
properties is also discussed.
相似文献
Peter Godfrey-SmithEmail: |
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Terry Harmer 《Cluster computing》2007,10(3):277-285
Gridcast is an R&D project investigating grid ideas and technologies in the broadcasting technical infrastructure. In this
paper I discuss the business and technical issues in building infrastructures to support broadcasters and outline the structure
of the Gridcast grid-based service oriented architecture for broadcasting playout support.
相似文献
Terry HarmerEmail: |
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This paper introduces a threshold policy with hysteresis (TPH) for the control of one-predator one-prey models. The models studied are the Lotka–Volterra and Rosenzweig–MacArthur
two species density-dependent predator–prey models and the Arditi–Ginzburg nondimensional ratio-dependent model. The proposed
policy (TPH) changes the dynamics of the system in such a way that a bounded oscillation is achieved confined to a region
that does not allow extinction of either species. The policy can be designed by a suitable choice of so called virtual equilibrium
points in a simple and intuitive manner.
相似文献
Amit Bhaya (Corresponding author)Email: |
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We develop a formal framework for the optimal allocation of limited resources that includes and clarifies the interplay between
individual optimization and the resulting effects at the population level. As an example, in regard to the evolution of sexual
recombination, the paradox of the twofold cost of sex is avoided by distinguishing between the evolution of recombination
and the subsequent emergence and stability of different mating types as a result of individual optimization within a population
that benefits from recombination.
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John PepperEmail: |
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Debates over adaptationism can be clarified and partially resolved by careful consideration of the ‘grain’ at which evolutionary
processes are described. The framework of ‘adaptive landscapes’ can be used to illustrate and facilitate this investigation.
We argue that natural selection may have special status at an intermediate grain of analysis of evolutionary processes. The
cases of sickle-cell disease and genomic imprinting are used as case studies.
相似文献
Peter Godfrey-SmithEmail: |
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Strategies of abstraction 总被引:2,自引:1,他引:1
Richard Levins 《Biology & philosophy》2006,21(5):741-755
Abstraction is seen as an active process which both enlightens and obscures. Abstractions are not true or false but relatively
enlightening or obscuring according to the problem under study; different abstractions may grasp different aspects of a problem.
Abstractions may be useless if they can answer questions only about themselves. A theoretical enterprise explores reality
through acluster of abstractions that use different perspectives, temporal and horizontal scales, and assumes different givens.
相似文献
Richard LevinsEmail: |
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Roger Sansom 《Biology & philosophy》2008,23(4):475-491
I show that gene regulation networks are qualitatively consistent and therefore sufficiently similar to linearly seperable
connectionist networks to warrant that the connectionist framework be applied to gene regulation. On this view, natural selection
designs gene regulation networks to overcome the difficulty of development. I offer some general lessons about their evolvability
that can be learned by examining the generic features of connectionist networks.
相似文献
Roger SansomEmail: |
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Roger Sansom 《Biology & philosophy》2009,24(4):441-459
One current version of the internalism/externalism debate in evolutionary theory focuses on the relative importance of developmental
constraints in evolutionary explanation. The received view of developmental constraints sees them as an internalist concept
that tend to be shared across related species as opposed to selective pressures that are not. Thus, to the extent that constraints
can explain anything, they can better explain similarity across species, while natural selection is better able to explain
their differences. I challenge both of these aspects of the received view and propose a hierarchical view of constraints.
相似文献
Roger SansomEmail: |