共查询到20条相似文献,搜索用时 31 毫秒
1.
In order to better understand and predict the release of proteins from bioerodible microspheres or nanospheres, it is important
to know the influences of different initial factors on the release mechanisms, though often it is difficult to assess what
exactly is at the origin of a certain dissolution profile. We propose here a new class of fine-grained multi-agent models
built to incorporate increasing complexity, permitting the exploration of the role of different parameters, especially that
of the internal morphology of the spheres, in the exhibited release profile. This approach, based on Monte Carlo (MC) and
cellular automata (CA) techniques, has permitted the testing of various assumptions and hypotheses about several experimental
systems of nanospheres encapsulating proteins. Results have confirmed that this modelling approach has increased the resolution
over the complexity involved, opening promising perspectives for future developments, especially complementing in vitro experimentation.
相似文献
Martin CraneEmail: |
2.
3.
4.
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: |
5.
6.
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: |
7.
The paper introduces a novel computational approach to brain dynamics modeling that integrates dynamic gene–protein regulatory
networks with a neural network model. Interaction of genes and proteins in neurons affects the dynamics of the whole neural
network. Through tuning the gene–protein interaction network and the initial gene/protein expression values, different states
of the neural network dynamics can be achieved. A generic computational neurogenetic model is introduced that implements this
approach. It is illustrated by means of a simple neurogenetic model of a spiking neural network of the generation of local
field potential. Our approach allows for investigation of how deleted or mutated genes can alter the dynamics of a model neural
network. We conclude with the proposal how to extend this approach to model cognitive neurodynamics.
相似文献
Nikola KasabovEmail: |
8.
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: |
9.
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: |
10.
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: |
11.
Leslie P. Francis Margaret P. Battin Jay Jacobson Charles Smith 《Journal of bioethical inquiry》2009,6(2):187-195
Syndromic surveillance uses new ways of gathering data to identify possible disease outbreaks. Because syndromic surveillance
can be implemented to detect patterns before diseases are even identified, it poses novel problems for informed consent, patient
privacy and confidentiality, and risks of stigmatization. This paper analyzes these ethical issues from the viewpoint of the
patient as victim and vector. It concludes by pointing out that the new International Health Regulations fail to take full
account of the ethical challenges raised by syndromic surveillance.
相似文献
Leslie P. FrancisEmail: |
12.
Chi-Li Yu Daniel Ferraro S. Ramaswamy Mark H. Schmitz Wayne F. Schaefer David T. Gibson 《Environmental Biology of Fishes》2008,82(1):51-58
A blue protein present in the mucus coating blue forms of walleye, Sander vitreus, was purified to homogeneity by a combination of ion exchange and hydrophobic interaction chromatography. The purified protein
has a molecular mass of 87,850 and is a homotetramer with a subunit molecular mass of 21,836. Solutions of the protein are
deep blue in color and show absorbance maxima at 383 and 633 nm, respectively. Acetone treatment of the protein releases a
blue chromophore with the spectral characteristics of biliverdin IXα. The results suggest that the blue protein is a new biliprotein
that we have termed Sandercyanin. The function of Sandercyanin is unknown, but limited amino acid sequence analysis suggests
it is a lipocalin that may be involved in the transport of heme degradation products.
相似文献
David T. GibsonEmail: |
13.
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: |
14.
15.
Stavros Ioannidis 《Biology & philosophy》2008,23(4):567-578
Evolutionary developmental biology (Evo-Devo) is a new and rapidly developing field of biology which focuses on questions
in the intersection of evolution and development and has been seen by many as a potential synthesis of these two fields. This
synthesis is the topic of the books reviewed here. Integrating Evolution and Development (edited by Roger Sansom and Robert
Brandon), is a collection of papers on conceptual issues in Evo-Devo, while From Embryology to Evo-Devo (edited by Manfred
Laubichler and Jane Maienschein) is a history of the problem of the relations between ontogeny and phylogeny.
相似文献
Stavros IoannidisEmail: |
16.
17.
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: |
18.
Service providers and their customers agree on certain quality of service guarantees through Service Level Agreements (SLA).
An SLA contains one or more Service Level Objectives (SLO)s that describe the agreed-upon quality requirements at the service
level. Translating these SLOs into lower-level policies that can then be used for design and monitoring purposes is a difficult
problem. Usually domain experts are involved in this translation that often necessitates application of domain knowledge to
this problem. In this article, we propose an approach that combines performance modeling with regression analysis to solve
this problem. We demonstrate that our approach is practical and that it can be applied to different n-tier services. Our experiments show that for a typical 3-tier e-commerce application in a virtualized environment, the SLA
can be met while improving CPU utilization by up to 3 times.
相似文献
Yuan ChenEmail: |
19.
Automated protein structure calculation from NMR data 总被引:3,自引:1,他引:2
Current software is almost at the stage to permit completely automatic structure determination of small proteins of <15 kDa,
from NMR spectra to structure validation with minimal user interaction. This goal is welcome, as it makes structure calculation
more objective and therefore more easily validated, without any loss in the quality of the structures generated. Moreover,
it releases expert spectroscopists to carry out research that cannot be automated. It should not take much further effort
to extend automation to ca 20 kDa. However, there are technological barriers to further automation, of which the biggest are
identified as: routines for peak picking; adoption and sharing of a common framework for structure calculation, including
the assembly of an automated and trusted package for structure validation; and sample preparation, particularly for larger
proteins. These barriers should be the main target for development of methodology for protein structure determination, particularly
by structural genomics consortia.
相似文献
Mike P. WilliamsonEmail: |
20.
Causal Explanation of Indonesian Forest Fires: Concepts, Applications, and Research Priorities 总被引:1,自引:0,他引:1
Andrew P. Vayda 《Human ecology: an interdisciplinary journal》2006,34(5):615-635
Problems with studies, claims, and assumptions that have been made about the causes of fires in Indonesia's tropical moist forests are identified, and the kinds of concepts, methods, prioritizing, and data needed to resolve the problems are discussed. Separate sections are devoted to studying ignitions, studying fire susceptibility and fire behavior, and using the goal of causal explanation to guide interdisciplinary research.
相似文献
Andrew P. VaydaEmail: |