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A lipid vesicle, or simply called a liposome, represents a synthetic compartment for the examination of transmembrane transport and signaling phenomena. Yet, a liposome is always subjected to size and shape fluctuations due to local and global imbalance of internal and external osmotic pressures. Here, we show that an osmotically stressed liposome placed within a hypotonic spherical bath undergoes cyclic dynamics described by a periodic sequence of swelling and relaxation phases. These two phases are interfaced by the appearance of a transient transmembrane pore through which chemical delivery occurs. An analytical model was formulated for the recurrent differential equations that convey the time-dependent swelling phase of a pulsatory liposome during individual cycles. We demonstrate that the time-dependent swelling phases of the last several cycles of a pulsatory liposome are strongly dependent on the size of the external bath. Furthermore, decreasing the size of the hypotonic medium reduces the number of cycles of a pulsatory liposome. Comparisons and contrasts of an infinite hypotonic bath with finite external baths of varying radii are discussed.

IntroductionThe main differences between the deterministic macroscopic models are to be found in pressure expressions and representation of various phases observed experimentally. MethodsIn this paper, using the laws of fluid dynamics and thermodynamics to describe the traffic flow reality, a new expression of pressure is made and a second order model is proposed. ResultsIt represents different traffic flow phases and, thus, conditions for transition between phases become clear. In addition, our approach suggests solutions to a number of problems yet to be resolved. Afterwards, simulations are presented which show some agreement with experimental data. ConclusionFinally, the proposed model highlights different types of possible actions for traffic flow control.

Abstract: This paper proposes the software package SISCON, dedicated to the evaluation of optimal decisions for large-scale systems. SISCON firstly evaluates mathematical models developed from experimental data using LS methods for linear and non-linear systems and after that computes the optimal decision problems, solving the mathematical non-linear programming problems. The large-scale systems have generally a complex structure and global approach computation cannot be carried out. The authors present a decentralised decision structure having a well-defined distribution of supervisory functions. After decomposition of large-scale problems is carried out, sub problems are solved using standard optimization techniques. SISCON offers opportunities for solving non-linear mathematical programming problems and for evaluating optimal decisions in large-scale systems control. [Copyright &y& Elsevier]

The paper presents some considerations about the design, refinement and accuracy of digital PID controllers. Starting from the robust-optimal design based on the sensitivity function of a continuous time PID controller, a discrete time equivalent is built. Several methods of quantization are introduced which improve the performances compared to the standard digital PID algorithm. Computational aspects and the efficiency of choosing the specific hardware support for PID algorithm implementation is discussed. Simulated results known that the achieved performances in closed loop implementation depend on the quality of design, but also of the rafinament and accuraccy of computed PID algorithm.

This paper presents the software package SISCON, dedicated to the evaluation of optimal decisions for large scale systems. SISCON firstly evaluates mathematical models developed out of experimental data using LS methods for linear and nonlinear systems and after that computes the optimal decision problems. The large scale systems have generally a complex structure and global approach computation cannot be carried out. The authors propose a descentralised decision structure having a well-defined distribution of supervisory functions. After decomposition of large - scale problems is carried out, subproblems are solved using standard optimization techniques. SISCON offers opportunities for solving non-linear mathematical programming problems and for evaluating optimal decisions in large scale systems control

In now-days, the PID controllers are still implemented in the industrial applications of automatic control. The purpose of this paper is to improve the PID standard algorithm evaluating the PID control output value by some numerical refined methods and by computational accuracy of the hardware support. The experimental results were obtained in simulation, using a second-order closed-loop system with a first order plant model with time delay.

The non-random mixing of biomembrane components, especially saturated phospholipids, exhibits important consequences in molecular biology. Particularly, the distribution of lipids within natural and model membranes is strongly determined by the selective association processes. These processes of phospholipids take place due to the cooperative modes in multiparticle systems as well as the specific lipid-lipid interactions both in the hydrophobic core and in the region of the polar headgroups. We demonstrated that the investigation of the selective association processes of saturated phospholipids might contribute to the insight of the lipid domains appearance inside the bilayer membranes. The association probabilities of like-pairs and cross-pairs from a binary mixture of saturated phospholipids were tested for both parallel and anti-parallel alignments of the polar headgroups. The present model confirms the experimental evidence for saturated phospholipids to have a high tendency for association in parallel configuration of the electric dipole moments of the polar headgroups whether the cross-sectional area of the polar headgroup is in an usual range of 25-55 Å2. There are three major lipid domains in a binary mixture of saturated phospholipids: (i) lipid domains in non-mixed phase of the first mixture component, in parallel alignment of the polar headgroups; (ii) lipid domains in non-mixed phase of the second mixture component, in anti-parallel alignment of the polar headgroups; (iii) lipid domains in mixed phase. We think that the selective association processes of phospholipids are neither exclusively, nor only involved in promoting the lipid domains appearance through bilayer phospholipid membranes.

Abstract: In a lysophospholipid binary mixture, there are three ways of association between the mixture components of single-chain amphiphiles: (a) between two identical molecules each of the first and second component (self-association process) and (b) between two different molecules (cross-association process). Association probabilities for three binary mixtures were analysed as functions depending on the electric dipole moments of the polar head groups. A 3-D view representation is most suitable for this analysis. The most important finding is that for certain values of the electric dipole moments there are molecular couples which have a maximum stability to the changes in the external electrolytic medium. This fact confirms the formation of clusters and their stability, which is equivalent to the existence of micro-heterogeneities within the lipid bilayers. On the other hand, there are unstable molecular associations, and this fact influences the appearance of some phase transitions. Generally, the increase of the electric dipole moment or the increase of the acyl-chain length of one component from a binary lipid mixture decreases the self-association probability between its own molecules, but it increases the self-association probability of the other mixture components. Furthermore, the cross-association probability has high values for any binary lipid mixture of single-chain amphiphiles.

The protocol described is designed for measurement, monitoring and control distributed systems in the field. It is a simple protocol, with reduced overhead, designed for stations with reduced intelligence level, using radio links. The protocol has elements situated in the levels 1, 2 and 7 of the OSI architecture. The level 7 service primitives implement functions specific for process monitoring and control and are all confirmed. They work on data objects as variables, domains, programs and events. The following topics are discussed: protocol structure, protocol efficiency, message optimal length, waiting queues length. An application of this protocol is shortly presented.