1,395 research outputs found
Variable-step finite difference schemes for the solution of Sturm-Liouville problems
We discuss the solution of regular and singular Sturm-Liouville problems by
means of High Order Finite Difference Schemes. We describe a code to define a
discrete problem and its numerical solution by means of linear algebra
techniques. Different test problems are proposed to emphasize the behaviour of
the proposed algorithm
Poly-Sarcosine and Poly(ethylene-glycol) interactions with proteins investigated using molecular dynamics simulations
Nanoparticles coated with hydrophilic polymers often show a reduction in
unspecific interactions with the biological environment, which improves their
biocompatibility. The molecular determinants of this reduction are not very
well understood yet, and their knowledge may help improving nanoparticle
design. Here we address, using molecular dynamics simulations, the interactions
of human serum albumin, the most abundant serum protein, with two promising
hydrophilic polymers used for the coating of therapeutic nanoparticles,
poly(ethylene-glycol) and poly-sarcosine. By simulating the protein immersed in
a polymer-water mixture, we show that the two polymers have a very similar
affinity for the protein surface, both in terms of the amount of polymer
adsorbed and also in terms of the type of amino acids mainly involved in the
interactions. We further analyze the kinetics of adsorption and how it affects
the polymer conformations. Minor differences between the polymers are observed
in the thickness of the adsorption layer, that are related to the different
degree of flexibility of the two molecules. In comparison poly-alanine, an
isomer of poly-sarcosine known to self-aggregate and induce protein
aggregation, shows a significantly larger affinity for the protein surface than
PEG and PSar, which we show to be related not to a different patterns of
interactions with the protein surface, but to the different way the polymer
interacts with water
New trends in technology and identity of traditional dairy and fermented meat production processes
Interest in ecofood tourism is strictly related to the consumption
of products associated with the geographical area visited.
Local products are often requested by consumers living far
from the production zones (e.g. in bistro restaurants that reproduce
the atmosphere of typicality). This phenomenon, if on the
one hand guaranteeing the continued popularity of certain
traditional foods, highlights the inherent dangers that certain
types of food pose. They could spread the risks to a much
wider area that they might typically inhabit. The higher the demand
for certain products, the more variations of the production
processes of the traditional products there will be. This is
particularly evident for fermented products that do not have
trademark protection which allows products made with
different technologies and/or raw materials to use the same
designation. This paper reports the strengths and the weaknesses
of traditional fermented food products, examining the
concept of typicality, and evidencing the risks associated
with consumption
Estimation of protein folding probability from equilibrium simulations
The assumption that similar structures have similar folding probabilities
() leads naturally to a procedure to evaluate for every
snapshot saved along an equilibrium folding-unfolding trajectory of a
structured peptide or protein. The procedure utilizes a structurally
homogeneous clustering and does not require any additional simulation. It can
be used to detect multiple folding pathways as shown for a three-stranded
antiparallel -sheet peptide investigated by implicit solvent molecular
dynamics simulations.Comment: 7 pages, 4 figures, supplemetary material
Bvps codes for solving optimal control problems
Optimal control problems arise in many applications and need suitable numerical methods to obtain a solution. The indirect methods are an interesting class of methods based on the Pontrya-gin’s minimum principle that generates Hamiltonian Boundary Value Problems (BVPs). In this paper, we review some general-purpose codes for the solution of BVPs and we show their efficiency in solving some challenging optimal control problems
Sharing feelings online: Studying emotional well-being via automated text analysis of Facebook posts
Digital traces of activity on social network sites represent a vast source of ecological data with potential connections with individual behavioral and psychological characteristics. The present study investigates the relationship between user-generated textual content shared on Facebook and emotional well-being. Self-report measures of depression, anxiety and stress were collected from 201 adult Facebook users from North Italy. Emotion-related textual indicators, including emoticon use, were extracted form users’ Facebook posts via automated text analysis. Correlation analyses revealed that individuals with higher levels of depression, anxiety expressed negative emotions on Facebook more frequently. In addition, use of emoticons expressing positive emotions correlated negatively with stress level. When comparing age groups, younger users reported higher frequency of both emotion-related words and emoticon use in their posts. Also, the relationship between online emotional expression and self-report emotional well-being was generally stronger in the younger group. Overall, findings support the feasibility and validity of studying individual emotional well-being by means of examination of Facebook profiles. Implications for online screening purposes and future research directions are discussed
- …