Physical landscapes in biological membranes: physico–chemical terrains for spatio–temporal control of biomolecular interactions and behaviour

2005 ◽  
Vol 363 (1827) ◽  
pp. 575-588 ◽  
Author(s):  
Paul O'Shea
Keyword(s):  
Biological Membranes ◽  
Point Of View ◽  
Membrane Rafts ◽  
Biomolecular Interactions ◽  
Membrane Dipole Potential ◽  
Physico Chemical ◽  
Spatio Temporal ◽  
Influential Parameters ◽  
Detection Technologies

The evolving complexities of biological membranes are discussed from the point of view of potential roles of the physical constitution of the membrane. These include features of the surface and dipole potentials and membrane ‘rafts’. These properties are outlined; they emphasize that protein–lipid and specific lipid environments are influential parameters in how biomolecular interactions may take place with and within membranes. Several fluorescence detection technologies directed towards measurement of these properties are also outlined that permit high–resolution experimental determination of intermolecular interactions with membranes by measuring small changes of these potentials. These point to the possibility that the membrane dipole potential in particular is enormously influential in determining the behaviour of receptor and signalling systems within membrane rafts, and offers the means of a novel mechanism for biological control.

Intermolecular interactions with/within cell membranes and the trinity of membrane potentials: kinetics and imaging

2003 ◽  
Vol 31 (5) ◽  
pp. 990-996 ◽  
Author(s):  
P. O'Shea
Keyword(s):  
Intermolecular Interactions ◽  
Cell Biology ◽  
Membrane Surface ◽  
Membrane Potentials ◽  
Membrane Microdomains ◽  
Membrane Dipole Potential ◽  
Additional Level ◽  
The Trinity ◽  
Detection Technologies

The interactions of (macro-)molecules with biological membranes underlies much of cell biology. This paper outlines many of the factors that must be taken into account in order to understand fully the nature of these interactions. These include some roles of the membrane potentials including features of the surface and dipole potentials. Several fluorescence detection technologies directed towards these are outlined that offer high-resolution experimental determination of the intermolecular interactions by measuring small changes of these potentials resulting from specific interactions of many kinds of molecular species. The possibilities for making single-cell spatial imaging measurements of such interactions is also described. Examples are used to indicate the feasibility of identifying and tracking localized interactions on the membrane surface in real-time. Some of this work points to the possibility that the membrane dipole potential spatially varies about the cell surface, particularly within membrane microdomains such as ‘rafts’. Such variation is suggested to underlie the altered behaviour of signalling systems within rafts and offer the means of an additional level of biological control.

Experimental Determination of Energy Demand and Spatio-Temporal Course of Pyrolysis for Various Materials

2012 ◽  
Vol 260-261 ◽  
pp. 598-604 ◽  
Author(s):  
Stanislav Honus ◽  
Ondřej Němček ◽  
Jaroslav Frantík ◽  
Veronika Sassmanová ◽  
Dagmar Juchelková
Keyword(s):  
Energy Demand ◽  
Point Of View ◽  
Process Conditions ◽  
Laboratory System ◽  
Horizontal Reactor ◽  
Temporal Course ◽  
Spatio Temporal ◽  
Reactor Space ◽  
Total Maximum

The article presents a detailed analysis of brown coal, rubber and polyethylene pyrolysis in a horizontal reactor of a thermic facility. It is a facility continuously processing entry materials flowing in the amount of up to 150 Kg.h -1 and with the total maximum heaters’ output of 200 kW. The attention has been paid to the thermal input of the pyrolysis process and to the description of physical-chemical processes in time and the reactor space. The objective has been to find out the best combination of entry material and process conditions from the point of view of pyrolysis energy intensity. The article specifics are based on the fact that the mentioned processes have been analysed in a large facility having the semi-production characteristics, not within a laboratory system used usually in this kind of research (DSC).

scholarly journals Determination of the true water content, the nature of the impurities and their concentration in transformer oil

2019 ◽  
Vol 124 ◽  
pp. 05005
Author(s):  
I.D. Gizzatova ◽  
V.K. Kozlov ◽  
D.M. Valiullina
Keyword(s):  
Moisture Content ◽  
Measurement Errors ◽  
Power Transformer ◽  
Operational Reliability ◽  
Point Of View ◽  
Transformer Oil ◽  
Physico Chemical ◽  
The Relationship ◽  
Insulating Properties

During the operation of transformers, the insulating oil is aging, therefore, there is the deterioration of its insulating properties, which is determined by multiple physico-chemical processes. The most dangerous factor, from the point of view of preserving the operational reliability and resource of a power transformer, is the moisture content of the insulation. Most methods for determining moisture content have measurement errors. These errors are largely dependent on impurities that are contained in the oil. The modified Fisher method proposed in the article allows determining the amount of impurities in the oil and the absolute moisture content. Conducted research allows also to determine the composition of impurities, to reveal the relationship between impurities and some parameters of transformer oil.

Factors Affecting Bond Strength between the Elements of Tires

1960 ◽  
Vol 33 (2) ◽  
pp. 556-580
Author(s):  
G. N. Buĭko ◽  
N. M. Arenzon ◽  
A. I. Tumanova ◽  
N. P. Zinchenko ◽  
N. A. Pruzhanskaya ◽  
...  
Keyword(s):  
Bond Strength ◽  
Point Of View ◽  
Factors Affecting ◽  
Synthetic Rubber ◽  
Decisive Importance ◽  
Physico Chemical ◽  
Technical Proficiency ◽  
Service Conditions ◽  
Butadiene Styrene

Abstract 1. Ply separation of tires is one of the essential factors reducing their mileage, particularly under difficult service conditions. Enhancement of the dynamic bond strength between elements of the tires is a most important line of study for increasing the mileage of tires based on synthetic rubber. 2. An analysis of defects in tires failing as a result of separation shows that for a given level of technical proficiency in handling synthetic rubber the adhesion type of separation between pliedup compounds or between rubber and cord (of viscose filament) is predominant. This form of failure is particularly characteristic of tires with vulcanizates based on butadiene/styrene rubber in all the main parts. 3. In investigations concerning separation phenomena in tires, decisive importance attaches to methods of determination of bond strength under conditions of dynamic loading of pliedup vulcanizates and rubber cord systems. We still do not have methods which could be regarded as fully satisfying the requirements proposed. However a series of methods have been provided which make it possible to assess, with an accuracy suitable for practical purposes, the effect of this or that factor upon the bond strength and to show the advantages and inadequacies of pliedup systems from the point of view of the operation of tires under actual service conditions. 4. The experimental results obtained show that the dynamic bond strength in pliedup systems, as also the endurance of the tires in relation to separation resistance, is determined by a complex body of physico-chemical and technological factors, by the construction of the articles, and also by the pattern of loading under repeated deformations. The general theoretical ideas developed in articles by some investigators, that the highest bond strength is to be achieved where full adhesion of the raw pliedup stocks takes place, as shown by the disappearance of boundaries between them, and that in all cases the factors which enhance the flowability of the stock enhance also the bond strength between them, were not confirmed experimentally.

Development and Pharmacokinetics Study of Antifungal Peptide Nanoliposomes by Liquid Chromatography-tandem Mass Spectrometry

2019 ◽  
Vol 15 (4) ◽  
pp. 312-318
Author(s):  
Shuoye Yang
Keyword(s):  
Mass Spectrometry ◽  
Biological Properties ◽  
Pharmacokinetic Property ◽  
Antifungal Peptide ◽  
Simple Liquid ◽  
Physico Chemical ◽  
Liquid Chromatography Tandem Mass ◽  
Pegylated Lipids

Background: The therapeutic ability and application of antifungal peptide (APs) are limited by their physico-chemical and biological properties, the nano-liposomal encapsulation would improve the in vivo circulation and stability. </P><P> Objective: To develop a long-circulating liposomal delivery systems encapsulated APs-CGA-N12 with PEGylated lipids and cholesterol, and investigated through in vivo pharmacokinetics. Methods: The liposomes were prepared and characterized, a rapid and simple liquid chromatographytandem mass spectrometry (LC-MS/MS) assay was developed for the determination of antifungal peptide in vivo, the pharmacokinetic characteristics of APs liposomes were evaluated in rats. Results: Liposomes had a large, unilamellar structure, particle size and Zeta potential ranged from 160 to 185 nm and -0.55 to 1.1 mV, respectively. The results indicated that the plasma concentration of peptides in reference solutions rapidly declined after intravenous administration, whereas the liposomeencapsulated ones showed slower elimination. The AUC(0-∞) was increased by 3.0-fold in liposomes in comparison with standard solution (20 mg·kg-1), the half-life (T1/2) was 1.6- and 1.5-fold higher compared to the reference groups of 20 and 40 mg·kg-1, respectively. Conclusion: Therefore, it could be concluded that liposomal encapsulation effectively improved the bioavailability and pharmacokinetic property of antifungal peptides.

Spatial-temporal data collection process models using mobile sinks

2019 ◽  
Vol 942 (12) ◽  
pp. 22-28
Author(s):  
A.V. Materuhin ◽  
V.V. Shakhov ◽  
O.D. Sokolova
Keyword(s):  
Energy Consumption ◽  
Operation Time ◽  
Point Of View ◽  
Process Models ◽  
Temporal Data ◽  
Network Nodes ◽  
Mobile Sinks ◽  
Autonomous Operation ◽  
Data Collection Process ◽  
Spatio Temporal

Optimization of energy consumption in geosensor networks is a very important factor in ensuring stability, since geosensors used for environmental monitoring have limited possibilities for recharging batteries. The article is a concise presentation of the research results in the area of increasing the energy consumption efficiency for the process of collecting spatio-temporal data with wireless geosensor networks. It is shown that in the currently used configurations of geosensor networks there is a predominant direction of the transmitted traffic, which leads to the fact that through the routing nodes that are close to the sinks, a much more traffic passes than through other network nodes. Thus, an imbalance of energy consumption arises in the network, which leads to a decrease in the autonomous operation time of the entire wireless geosensor networks. It is proposed to use the possible mobility of sinks as an optimization resource. A mathematical model for the analysis of the lifetime of a wireless geosensor network using mobile sinks is proposed. The model is analyzed from the point of view of optimization energy consumption by sensors. The proposed approach allows increasing the lifetime of wireless geosensor networks by optimizing the relocation of mobile sinks.

scholarly journals Evaluation of the Ability to Accurately Produce Angular Details by 3D Printing of Plastic Parts

Machines ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 150
Author(s):  
Andrei Marius Mihalache ◽  
Gheorghe Nagîț ◽  
Laurențiu Slătineanu ◽  
Adelina Hrițuc ◽  
Angelos Markopoulos ◽  
...  
Keyword(s):  
3D Printing ◽  
Point Of View ◽  
Vertex Angle ◽  
Function Type ◽  
Constant Height ◽  
3D Printers ◽  
3D Printed ◽  
Mathematical Processing ◽  
Plastic Parts

3D printing is a process that has become widely used in recent years, allowing the production of parts with relatively complicated shapes from metallic and non-metallic materials. In some cases, it is challenging to evaluate the ability of 3D printers to make fine details of parts. For such an assessment, the printing of samples showing intersections of surfaces with low angle values was considered. An experimental plan was designed and materialized to highlight the influence of different factors, such as the thickness of the deposited material layer, the printing speed, the cooling and filling conditions of the 3D-printed part, and the thickness of the sample. Samples using areas in the form of isosceles triangles with constant height or bases with the same length, respectively, were used. The mathematical processing of the experimental results allowed the determination of empirical mathematical models of the power-function type. It allowed the detection of both the direction of actions and the intensity of the influence exerted by the input factors. It is concluded that the strongest influence on the printer’s ability to produce fine detail, from the point of view addressed in the paper, is exerted by the vertex angle, whose reduction leads to a decrease in printing accuracy.

Determination of a Rubber-Like Material Model as an Inverse Problem

2011 ◽  
Vol 70 ◽  
pp. 225-230 ◽  
Author(s):  
Agnieszka Derewonko ◽  
Andrzej Kiczko
Keyword(s):  
Selection Process ◽  
Axial Stress ◽  
Constitutive Models ◽  
Material Model ◽  
Polyester Fabric ◽  
Point Of View ◽  
Air Cushion ◽  
Ill Conditioning ◽  
Stress States

The purpose of this paper is to describe the selection process of a rubber-like material model useful for simulation behaviour of an inflatable air cushion under multi-axial stress states. The air cushion is a part of a single segment of a pontoon bridge. The air cushion is constructed of a polyester fabric reinforced membrane such as Hypalon®. From a numerical point of view such a composite type poses a challenge since numerical ill-conditioning can occur due to stiffness differences between rubber and fabric. Due to the analysis of the large deformation dynamic response of the structure, the LS-Dyna code is used. Since LS-Dyna contains more than two-hundred constitutive models the inverse method is used to determine parameters characterizing the material on the base of results of the experimental test.

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