Search results for "Monte Carlo method."
showing 10 items of 1217 documents
Cellular uptake and in vitro antitumor efficacy of composite liposomes for neutron capture therapy.
2014
Background Neutron capture therapy for glioblastoma has focused mainly on the use of 10B as neutron capture isotope. However, 157Gd offers several advantages over boron, such as higher cross section for thermal neutrons and the possibility to perform magnetic resonance imaging during neutron irradiation, thereby combining therapy and diagnostics. We have developed different liposomal formulations of gadolinium-DTPA (Magnevist®) for application in neutron capture therapy of glioblastoma. The formulations were characterized physicochemically and tested in vitro in a glioma cell model for their effectiveness. Methods Liposomes entrapping gadolinium-DTPA as neutron capture agent were manufactur…
GAUSSIAN EFFECTIVE POTENTIAL AND ANTIFERROMAGNETISM IN THE HUBBARD MODEL
2012
The Gaussian Effective Potential (GEP) is shown to be a useful variational tool for the study of the magnetic properties of strongly correlated electronic systems. The GEP is derived for a single band Hubbard model on a two-dimensional bi-partite square lattice in the strong coupling regime. At half-filling the antiferromagnetic order parameter emerges as the minimum of the effective potential with an accuracy which improves over RPA calculations and is very close to that achieved by Monte Carlo simulations. Extensions to other magnetic systems are discussed.
Experimental-Like Affinity Constants and Enantioselectivity Estimates from Flexible Docking
2012
Experimental-like affinity constants and enantioselectivity estimates, not predicted so far computationally, were obtained using a novel flexible modeling/docking combined strategy. The S- and R-warfarin-human serum albumin (HSA, site I) complexes were used as an interaction model. The process for a verified estimation includes the following: (i) ionized open chain forming at physiological pH (a recent focus); (ii) conformational search (molecular mechanics and Monte Carlo methods); (iii) rigid protein-flexible ligand docking (GlideXP) generating low energy paired S- and R-poses; (iv) graphical comparison against the X-ray crystal structure (unsatisfactory verification step); (v) quantum po…
An optimization approach for efficient management of EV parking lots with batteries recharging facilities
2013
In this paper an optimization approach to devise efficient management strategies for Electric Vehicles parking lots is proposed. A Monte Carlo approach is used to evaluate the load consumption profile for groups of Electric Vehicles showing different features. The Monte Carlo approach allows to combine the different social and economical features affecting the commercial penetration of Electric Vehicles with the technical aspects. The basic feature to be assessed is the initial State Of Charge, which in turn depends on the distance travelled by the vehicle since the last recharge and thus by the usage of the vehicle (private, professional). The model is then used to optimize some objective …
Modelling the carbon Snoek peak in ferrite: Coupling molecular dynamics and kinetic Monte-Carlo simulations
2008
Abstract Molecular statics, molecular dynamics and kinetic Monte-Carlo are used to model the carbon Snoek peak in ferrite. Using an interatomic EAM potential for the Fe–C system, saddle point energies for the diffusion of carbon have been evaluated under uniaxial stress by molecular statics. These energies have been reintroduced in a kinetic Monte-Carlo scheme to predict the repartition of carbon atoms in different octahedral sites. This repartition leads to an anelastic deformation calculated by molecular dynamics, which causes internal friction (the Snoek peak) for cyclic stress. This approach leads to quantitative predictions of the internal friction, which are in good agreement with exp…
Accurate representation of the distributions of the 3D Poisson-Voronoi typical cell geometrical features
2019
Understanding the intricate and complex materials microstructure and how it is related to materials properties is an important problem in the Materials Science field. For a full comprehension of this relation, it is fundamental to be able to describe the main characteristics of the 3-dimensional microstructure. The most basic model used for approximating steel microstructure is the Poisson-Voronoi diagram. Poisson-Voronoi diagrams have interesting mathematical properties, and they are used as a good model for single-phase materials. In this paper we exploit the scaling property of the underlying Poisson process to derive the distribution of the main geometrical features of the grains for ev…
A comparison of two indirect methods for estimating average levels of gene flow using microsatellite data.
1999
We compare the performance of Nm estimates based on FST and RST obtained from microsatellite data using simulations of the stepwise mutation model with range constraints in allele size classes. The results of the simulations suggest that the use of microsatellite loci can lead to serious overestimations of Nm, particularly when population sizes are large (N5000) and range constraints are high (K20). The simulations also indicate that, when population sizes are small (N/= 500) and migration rates are moderate (Nm approximately 2), violations to the assumption used to derive the Nm estimators lead to biased results. Under ideal conditions, i.e. large sample sizes (ns/= 50) and many loci (nl/=…
Social relations in older adults: Secular trends and longitudinal changes over a 16-year follow-up.
2010
Abstract Drawing on population studies in Finland, we investigated secular trends and longitudinal changes in social relations. The cohort comparison data comprised on 974 persons aged 65–69 years from three cohorts born between 1919 and 1939 and interviewed in 1988, 1996 and 2004. Longitudinal analyses were conducted for 635 persons aged 65–74 years over a 16-year follow-up at three measurement points. Social relations were studied on the basis of frequency seeing one's offspring, perceptions of the sufficiency of these contacts, and by asking whom the participants considered as their closest person and how often and in how many tasks they helped someone. The cohort comparisons showed that…
Phase behaviour of heteronuclear dimers in three-dimensional systems—a Monte Carlo study
2008
Monte Carlo simulation in the grand canonical ensemble, the histogram reweighting technique and finite size scaling are used to study the phase behaviour of dimers in three-dimensional systems. A single molecule is composed of two segments A and B, and the bond between them cannot be broken. The phase diagrams have been estimated for a set of model systems. Different structures formed by heteronuclear dimers have been found. The results show a great variety of vapour–liquid coexistence behaviour depending on the strength of the interactions between segments.
Analyzing Protein-Protein Spatial-Temporal Dependencies from Image Sequences Using Fuzzy Temporal Random Sets
2008
Total Internal Reflection Fluorescence Microscopy (TIRFM) allows us to image fluorescenttagged proteins near the plasma membrane of living cells with high spatial-temporal resolution. Using TIRFM imaging of GFP-tagged clathrin endocytic proteins, areas of fluorescence are observed as overlapping spots of different sizes and durations. Standard procedures to measure protein-protein colocalization of dual labeled samples threshold the original graylevel images to segment areas covered by different proteins. This binary logic is not appropriate as it leaves a free tuning parameter which can influence the conclusions. Moreover, these procedures rely on simple statistical analysis based on corre…