Kazimierz Dworecki | Jan Kochanowski University in Kielce (original) (raw)

Papers by Kazimierz Dworecki

Research paper thumbnail of ORIGINAL PAPER Laser interferometric investigation of solute transport through membrane-concentration boundary layer system

We investigate diffusive transport in a membrane system with a horizontally mounted membrane unde... more We investigate diffusive transport in a membrane system with a horizontally mounted membrane under concentration polarization conditions performed by a laser inter-ferometry method. The data obtained from two different theoretical models are compared to the experimental results of the substance flux. In the first model, the membrane is considered as infinitely thin, while in the second one as a wall of finite thickness. The theoretical calculations show sufficient correspondence with the experimental results. On the basis of interferometric measurements, the relative permeability coefficient (ζs) for the system, consisting of the membrane and concentration boundary layers, was also obtained. This coefficient reflects the concentration polarization of the membrane system. The obtained results indicate that the coefficient ζs of the membrane-concentration boundary layer system decreases in time and seems to be independent of the initial concentration of the solute.

Research paper thumbnail of Determination of the membrane permeability coefficient under concentration polarisation conditions

Desalination, 2006

... 123 131.[16] R. Rautenbach and R. Albrecht, Membrane Proceses,Wiley, New York, 1989.[17] EI C... more ... 123 131.[16] R. Rautenbach and R. Albrecht, Membrane Proceses,Wiley, New York, 1989.[17] EI Cussler, Diffusion Mass Transfer in ... techniques of transportthrough membranes, Desalination, 59 (1986) 105 198.[22] K. Dworecki, S. W sik and A. l zak, Temporal andspatial ...

Research paper thumbnail of Effect of concentration boundary layers on passive solute flows in a system of two polymeric membranes positioned in vertical planes

Polymers in Medicine, 2003

The results of studies of influence of concentration boundary layers on passive diffusive transpo... more The results of studies of influence of concentration boundary layers on passive diffusive transport in a double-membrane osmo-diffusive cell, containing a series of two (Ml and M(r)) vertically positioned, flat, microporous and symmetric polymer membranes (Nephrophane and Cellulose IMP-1) are presented in this paper. The membranes separated three compartments (l, m, r) containing binary, heterogeneous and non-ionic solutions (aqueous solutions of glucose or ethanol) or ternary non-electrolyte solutions (glucose solutions in 0.75 mol.l-1 solution of ethanol or ethanol solutions in 0.1 mol.l-1 aqueous solution of glucose). Solution concentrations fulfilled the condition C(k)l > C(k)m > C(k)r. The intermembrane compartment (m) was an infinitesimal solution layer. The volume of the m compartment and the volumes of the external (l and r) compartments fulfilled the condition Vl = Vr approximately 170 Vm. The tests were performed for configurations A and B of a double-membrane osmo-d...

Research paper thumbnail of The diffusion of antibiotics throught an artificial membrane in the presence of Proteus vulgaris O25 lipopolysaccharides

Research paper thumbnail of Laser interferometric analysis of glucose and sucrose diffusion in agarose gel

General physiology and biophysics, 2014

The paper presents the investigation results of glucose and sucrose diffusion in agarose gel stud... more The paper presents the investigation results of glucose and sucrose diffusion in agarose gel studied with laser interferometry method and the results of fluorescence analysis of the macroscopic gel structure. The diffusion kinetics of these substances released from aqueous solutions of a molar concentration of 0.05 M into the agarose solutions of concentrations of 0.5% and 3% in two gravitational configurations of measuring system was analysed. In the first configuration the solute diffused according, whereas in the second one -opposite to the gravitational force. The diffusion was analysed in the time period between 120 and 2400 s with a time interval of ∆t = 120 s. We observed that the convective instabilities were damped well by the agarose gel, which gives the possibility of the interferometric studies of the diffusive transport for other substances in different gravitational configurations of the system. The time characteristics of glucose and sucrose fluxes in both configurations of the system and the gravitational polarisation coefficient values were obtained. The substantial differences in fluxes of glucose and sucrose diffused according and opposite to the gravitational force were observed. Additionally, we observed the differences between the diffusive fluxes of these substances in both configurations in dependence on the gel solution concentration (which is associated with gel porosity dependent on its concentration) and the kind of diffused substance.

Research paper thumbnail of Effect of concentration boundary layers on passive solute flows in a system of two polymeric membranes positioned in vertical planes

The results of studies of influence of concentration boundary layers on passive diffusive transpo... more The results of studies of influence of concentration boundary layers on passive diffusive transport in a double-membrane osmo-diffusive cell, containing a series of two (Ml and M(r)) vertically positioned, flat, microporous and symmetric polymer membranes (Nephrophane and Cellulose IMP-1) are presented in this paper. The membranes separated three compartments (l, m, r) containing binary, heterogeneous and non-ionic solutions (aqueous solutions of glucose or ethanol) or ternary non-electrolyte solutions (glucose solutions in 0.75 mol.l-1 solution of ethanol or ethanol solutions in 0.1 mol.l-1 aqueous solution of glucose). Solution concentrations fulfilled the condition C(k)l > C(k)m > C(k)r. The intermembrane compartment (m) was an infinitesimal solution layer. The volume of the m compartment and the volumes of the external (l and r) compartments fulfilled the condition Vl = Vr approximately 170 Vm. The tests were performed for configurations A and B of a double-membrane osmo-d...

Research paper thumbnail of Gravitational effects on transmembrane flux: the rayleigh�taylor convective instability

Journal of Membrane Science, Mar 1, 1985

ABSTRACT Using a cell with horizontally mounted membranes, volume flux was measured as a function... more ABSTRACT Using a cell with horizontally mounted membranes, volume flux was measured as a function of gravitational geometry. Water was placed on one side of the membrane. The opposite side of the membrane was exposed to either aqueous glucose solutions, with densities greater than water; or aqueous ethanol, less dense than water; or ethanol—glucose—water solutions. In all cases, the osmotic pressure gradient generated volume flux from water to the solution. No mechanical stirring was used.Experiments were performed first with water above the membrane and the solution below it. They were then repeated with water below and the solution above the membrane. In all cases, volume flux was significantly larger when the denser liquid was above the membrane.Mach—Zehnder interferograms were obtained for the interface region of the water—membrane—0.1 M glucose system, Results show directly that boundary layers are substantially larger and more uniform with the lower-density liquid above the membrane than with the opposite geometry.These experimental findings are interpreted in terms of a convective gravitational instability that reduces boundary layer dimensions and increases volume flux. Following Rayleigh—Tavlor analysis of fluid gravitational stability, a concentration-gradient Rayleigh Number is developed and used in a mathematical model for gravitationally sensitive volume flux.

Research paper thumbnail of Influence of gravitational field on substance transport in gels

Journal of Membrane Science, 2010

This paper presents an investigation of substance transport in an aqueous solution-gel system. In... more This paper presents an investigation of substance transport in an aqueous solution-gel system. In gels, free convection is damped and hydrodynamic instabilities do not occur, so it is possible to determine the influence of gravity on substance transport. With the aid of a laser interferometric method, specific experiments were performed under conditions in which the substance diffuses according to and against the gravitational force. The concentration profiles and the substance flows were calculated on the basis of interference image analysis. Comparison of the results indicates a noticeable influence of gravitational field on passive substance transport. The gravitational field significantly modifies the amount of transported substance and affects the concentration profiles as well as the time evolution of the concentration field.

Research paper thumbnail of Subdiffusive model of substance releasing from a thick membrane

We study both theoretically and experimentally the process of subdiffusive substance releasing fr... more We study both theoretically and experimentally the process of subdiffusive substance releasing from a thick membrane. The theoretical model uses the subdiffusion equation with fractional time derivative and specific boundary conditions at the membrane surfaces. Using a special \textit{ansatz} we find analytical formulas describing the time evolution of concentration profiles and an amount of the substance remains in the membrane.

Research paper thumbnail of We propose a method to extract from experimental data the subdiffusion parameterand subdif- fusion coefficient Dwhich are defined by means of the relation h x2i = 2D

� (1+ �) t � where h x2i denotes a mean square displacement of a random walker starting from x = ... more � (1+ �) t � where h x2i denotes a mean square displacement of a random walker starting from x = 0 at the initial time t = 0. The method exploits a membrane system where a substance of interest is transported in a solvent from one vessel to another across a thin membrane which plays here only an auxiliary role. Using such a system, we experimentally study a diffusion of glucose and sucrose in a gel solvent. We find a fully analytic solution of the fractional subdiffusion equation with the initial and boundary conditions representing the system under study. Confronting the experimental data with the derived formulas, we show a subdiffusive character of the sugar transport in gel solvent. We precisely determine the parameter �, which is smaller than 1, and the subdiffusion coefficient D�.

Research paper thumbnail of Application of Two-Membrane System to Measure Subdiffusion Coefficients

Acta Physica Polonica Series B

Comparing the experimental results to theoretical functions, we estimate the subdiffusion coeffic... more Comparing the experimental results to theoretical functions, we estimate the subdiffusion coefficient of PEG2000 in agarose gel. The experiment was performed with the two-membrane system where thin membranes separated homogeneous solution of PEG2000 for pure solvent at an initial moment. The theoretical function was found by solving analytically the subdiffusion equation.

Research paper thumbnail of Subdiffusion in a Membrane System

The subdiffusion is defined by the relation delimiter < (Delta x)2> ˜ talpha with alpha &lt... more The subdiffusion is defined by the relation delimiter < (Delta x)2> ˜ talpha with alpha < 1. We present a new method of calculating the coefficient alpha , which can be used to obtain it experimentally. The method refers to the time evolution of the thickness of the so-called near-membrane layers.

Research paper thumbnail of Laser interferometric investigation of solute transport through membrane-concentration boundary layer system

Journal of Biological Physics, 2015

We investigate diffusive transport in a membrane system with a horizontally mounted membrane unde... more We investigate diffusive transport in a membrane system with a horizontally mounted membrane under concentration polarization conditions performed by a laser interferometry method. The data obtained from two different theoretical models are compared to the experimental results of the substance flux. In the first model, the membrane is considered as infinitely thin, while in the second one as a wall of finite thickness. The theoretical calculations show sufficient correspondence with the experimental results. On the basis of interferometric measurements, the relative permeability coefficient (ζ s ) for the system, consisting of the membrane and concentration boundary layers, was also obtained. This coefficient reflects the concentration polarization of the membrane system. The obtained results indicate that the coefficient ζ s of the membrane-concentration boundary layer system decreases in time and seems to be independent of the initial concentration of the solute.

Research paper thumbnail of A total internal reflection ellipsometry and atomic force microscopy study of interactions between Proteus mirabilis lipopolysaccharides and antibodies

European Biophysics Journal, 2015

Specific antigen-antibody interactions play a central role in the human immune system. The object... more Specific antigen-antibody interactions play a central role in the human immune system. The objective of this paper is to detect immune complexes using label-free detection techniques, that is, total internal reflection ellipsometry (TIRE) and atomic force microscopy (AFM)-based topography and recognition imaging. Interactions of purified rabbit immunoglobulin G (IgG) antibodies with bacterial endotoxins (Proteus mirabilis S1959 O3 lipopolysaccharides) were studied. Lipopolysaccharide was adsorbed on gold surface for TIRE. In the AFM imaging experiments, LPS was attachment to the PEG linker (AFM tip modification). The mica surface was covered by IgG. In TIRE, the optical parameters Ψ and Δ change when a complex is formed. It was found that even highly structured molecules, such as IgG antibodies (anti-O3 LPS rabbit serum), preserve their specific affinity to their antigens (LPS O3). LPS P. mirabilis O3 response of rabbit serum anti-O3 was also tested by topography and recognition imaging. Both TIRE and AFM techniques were recruited to check for possible detection of antigen-antibody recognition event. The presented data allow for determination of interactions between a variety of biomolecules. In future research, this technique has considerable potential for studying a wide range of antigen-antibody interactions and its use may be extended to other biomacromolecular systems.

Research paper thumbnail of Gravitational effects in a passive transmembrane transport: the flux graviosmotic and gravidiffusive effects in non-electrolytes

Journal of biological physics, 2000

In this paper the classification ofthe gravitational effects in a passive transmembranetransport ... more In this paper the classification ofthe gravitational effects in a passive transmembranetransport is presented. Among these effects there arethe flux and force gravitational effects (fluxgraviosmotic effect, osmotic pressure graviosmoticeffect, flux gravidiffusive effect, osmotic pressuregravidiffusive effect, voltage gravielectric effectand current gravielectric effect). The volume fluxgraviosmotic and solute flux gravidiffusive effectsmodel equations for a single-membrane system areelaborated. These models for binary and ternarynon-electrolyte solutions have been verified using anexperimental data volume and solute fluxes forosmotic-diffusion cell with horizontally mountedmembrane. In the experimental set-up, water was placedon one side of the membrane. The opposite side of themembrane was exposed to binary or ternary solutions ofdensities greater than that of water (aqueous glucoseor glucose-0.2 mole/l aqueous ethanol) and binary andternary solutions of densities larger than that ...

Research paper thumbnail of Thermodynamic model equations for heterogeneous multicomponent non-ionic solution transport in a multimembrane system

Journal of biological physics, 1999

Non-equilibrium thermodynamic model equations for non-ionic and heterogeneous n-component solutio... more Non-equilibrium thermodynamic model equations for non-ionic and heterogeneous n-component solution transport in a m-membrane system are presented. This model is based on two equations. The first one describes the volume transport of the solution and the second the transport of the solute. Definitions of the hydraulic permeability, reflection and diffusive permeability coefficients of the m-membrane system and relations between the coefficients of the m-membrane system and the respective membranes of the system are also given. The validity of this model for binary and ternary solutions was verified, using a double-membrane cell with a horizontally mounted membrane. In the cell, volume and solute fluxes were measured as a function of concentration and gravitational configuration.

Research paper thumbnail of The Investigation of Time-dependent Solute Transport through Horizontally Situated Membrane: The Effect of Configuration Membrane System

Journal of biological physics, 1997

This paper presents an experimental and theoretical investigation ofsolute transport through a ho... more This paper presents an experimental and theoretical investigation ofsolute transport through a horizontally situated membrane. Theexperimental investigation was carried out by the laserinterferometric method in association with a computer system ofinterference image analysis. On the basis of this analysis thicknessof near-membrane layers, solution concentration drops on these layersas well as diffusion fluxes of diluted substance are determined.Different fluxes of the soluble substance are observed depending onthe configuration of the system. The results of the experimental andtheoretical investigation of diffusion fluxes are conformable inrespect of measurement error, with one adjustment parameter, i.e. thesolute partition coefficient.

Research paper thumbnail of Surface modification of PET membrane by ion implantation

Vacuum, 2007

Semicrystalline poly(ethylene terephtalate) (PET) foils were irradiated with N 5+ , O 7+ and C 3+... more Semicrystalline poly(ethylene terephtalate) (PET) foils were irradiated with N 5+ , O 7+ and C 3+ ions. Ions beams of 50 keV N 5+ , 70 keV O 7+ and 30 keV C 3+ were produced from the ECR ion source. The induced effects and wettability of ion-implanted membranes were investigated by means of the Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and by the contactangle methods. FTIR measurements of the virgin and irradiated samples show the scission processes of main chains at the ethylene glycol residue. Various degradation processes known from photochemical degradation were also observed. The AFM observation revealed that the surface topography changes after irradiation. The contact-angle measurements showed that the PET membranes became significantly more hydrophilic after the ion irradiation. r

Research paper thumbnail of Laser interferometric analysis of glucose and sucrose diffusion in agarose gel

General physiology and biophysics, 2014

The paper presents the investigation results of glucose and sucrose diffusion in agarose gel stud... more The paper presents the investigation results of glucose and sucrose diffusion in agarose gel studied with laser interferometry method and the results of fluorescence analysis of the macroscopic gel structure. The diffusion kinetics of these substances released from aqueous solutions of a molar concentration of 0.05 M into the agarose solutions of concentrations of 0.5% and 3% in two gravitational configurations of measuring system was analysed. In the first configuration the solute diffused according, whereas in the second one -opposite to the gravitational force. The diffusion was analysed in the time period between 120 and 2400 s with a time interval of ∆t = 120 s. We observed that the convective instabilities were damped well by the agarose gel, which gives the possibility of the interferometric studies of the diffusive transport for other substances in different gravitational configurations of the system. The time characteristics of glucose and sucrose fluxes in both configurations of the system and the gravitational polarisation coefficient values were obtained. The substantial differences in fluxes of glucose and sucrose diffused according and opposite to the gravitational force were observed. Additionally, we observed the differences between the diffusive fluxes of these substances in both configurations in dependence on the gel solution concentration (which is associated with gel porosity dependent on its concentration) and the kind of diffused substance.

Research paper thumbnail of Effect of concentration boundary layers on passive solute flows in a system of two polymeric membranes positioned in vertical planes

Polimery w medycynie, 2003

The results of studies of influence of concentration boundary layers on passive diffusive transpo... more The results of studies of influence of concentration boundary layers on passive diffusive transport in a double-membrane osmo-diffusive cell, containing a series of two (Ml and M(r)) vertically positioned, flat, microporous and symmetric polymer membranes (Nephrophane and Cellulose IMP-1) are presented in this paper. The membranes separated three compartments (l, m, r) containing binary, heterogeneous and non-ionic solutions (aqueous solutions of glucose or ethanol) or ternary non-electrolyte solutions (glucose solutions in 0.75 mol.l-1 solution of ethanol or ethanol solutions in 0.1 mol.l-1 aqueous solution of glucose). Solution concentrations fulfilled the condition C(k)l > C(k)m > C(k)r. The intermembrane compartment (m) was an infinitesimal solution layer. The volume of the m compartment and the volumes of the external (l and r) compartments fulfilled the condition Vl = Vr approximately 170 Vm. The tests were performed for configurations A and B of a double-membrane osmo-d...

Research paper thumbnail of ORIGINAL PAPER Laser interferometric investigation of solute transport through membrane-concentration boundary layer system

We investigate diffusive transport in a membrane system with a horizontally mounted membrane unde... more We investigate diffusive transport in a membrane system with a horizontally mounted membrane under concentration polarization conditions performed by a laser inter-ferometry method. The data obtained from two different theoretical models are compared to the experimental results of the substance flux. In the first model, the membrane is considered as infinitely thin, while in the second one as a wall of finite thickness. The theoretical calculations show sufficient correspondence with the experimental results. On the basis of interferometric measurements, the relative permeability coefficient (ζs) for the system, consisting of the membrane and concentration boundary layers, was also obtained. This coefficient reflects the concentration polarization of the membrane system. The obtained results indicate that the coefficient ζs of the membrane-concentration boundary layer system decreases in time and seems to be independent of the initial concentration of the solute.

Research paper thumbnail of Determination of the membrane permeability coefficient under concentration polarisation conditions

Desalination, 2006

... 123 131.[16] R. Rautenbach and R. Albrecht, Membrane Proceses,Wiley, New York, 1989.[17] EI C... more ... 123 131.[16] R. Rautenbach and R. Albrecht, Membrane Proceses,Wiley, New York, 1989.[17] EI Cussler, Diffusion Mass Transfer in ... techniques of transportthrough membranes, Desalination, 59 (1986) 105 198.[22] K. Dworecki, S. W sik and A. l zak, Temporal andspatial ...

Research paper thumbnail of Effect of concentration boundary layers on passive solute flows in a system of two polymeric membranes positioned in vertical planes

Polymers in Medicine, 2003

The results of studies of influence of concentration boundary layers on passive diffusive transpo... more The results of studies of influence of concentration boundary layers on passive diffusive transport in a double-membrane osmo-diffusive cell, containing a series of two (Ml and M(r)) vertically positioned, flat, microporous and symmetric polymer membranes (Nephrophane and Cellulose IMP-1) are presented in this paper. The membranes separated three compartments (l, m, r) containing binary, heterogeneous and non-ionic solutions (aqueous solutions of glucose or ethanol) or ternary non-electrolyte solutions (glucose solutions in 0.75 mol.l-1 solution of ethanol or ethanol solutions in 0.1 mol.l-1 aqueous solution of glucose). Solution concentrations fulfilled the condition C(k)l > C(k)m > C(k)r. The intermembrane compartment (m) was an infinitesimal solution layer. The volume of the m compartment and the volumes of the external (l and r) compartments fulfilled the condition Vl = Vr approximately 170 Vm. The tests were performed for configurations A and B of a double-membrane osmo-d...

Research paper thumbnail of The diffusion of antibiotics throught an artificial membrane in the presence of Proteus vulgaris O25 lipopolysaccharides

Research paper thumbnail of Laser interferometric analysis of glucose and sucrose diffusion in agarose gel

General physiology and biophysics, 2014

The paper presents the investigation results of glucose and sucrose diffusion in agarose gel stud... more The paper presents the investigation results of glucose and sucrose diffusion in agarose gel studied with laser interferometry method and the results of fluorescence analysis of the macroscopic gel structure. The diffusion kinetics of these substances released from aqueous solutions of a molar concentration of 0.05 M into the agarose solutions of concentrations of 0.5% and 3% in two gravitational configurations of measuring system was analysed. In the first configuration the solute diffused according, whereas in the second one -opposite to the gravitational force. The diffusion was analysed in the time period between 120 and 2400 s with a time interval of ∆t = 120 s. We observed that the convective instabilities were damped well by the agarose gel, which gives the possibility of the interferometric studies of the diffusive transport for other substances in different gravitational configurations of the system. The time characteristics of glucose and sucrose fluxes in both configurations of the system and the gravitational polarisation coefficient values were obtained. The substantial differences in fluxes of glucose and sucrose diffused according and opposite to the gravitational force were observed. Additionally, we observed the differences between the diffusive fluxes of these substances in both configurations in dependence on the gel solution concentration (which is associated with gel porosity dependent on its concentration) and the kind of diffused substance.

Research paper thumbnail of Effect of concentration boundary layers on passive solute flows in a system of two polymeric membranes positioned in vertical planes

The results of studies of influence of concentration boundary layers on passive diffusive transpo... more The results of studies of influence of concentration boundary layers on passive diffusive transport in a double-membrane osmo-diffusive cell, containing a series of two (Ml and M(r)) vertically positioned, flat, microporous and symmetric polymer membranes (Nephrophane and Cellulose IMP-1) are presented in this paper. The membranes separated three compartments (l, m, r) containing binary, heterogeneous and non-ionic solutions (aqueous solutions of glucose or ethanol) or ternary non-electrolyte solutions (glucose solutions in 0.75 mol.l-1 solution of ethanol or ethanol solutions in 0.1 mol.l-1 aqueous solution of glucose). Solution concentrations fulfilled the condition C(k)l > C(k)m > C(k)r. The intermembrane compartment (m) was an infinitesimal solution layer. The volume of the m compartment and the volumes of the external (l and r) compartments fulfilled the condition Vl = Vr approximately 170 Vm. The tests were performed for configurations A and B of a double-membrane osmo-d...

Research paper thumbnail of Gravitational effects on transmembrane flux: the rayleigh�taylor convective instability

Journal of Membrane Science, Mar 1, 1985

ABSTRACT Using a cell with horizontally mounted membranes, volume flux was measured as a function... more ABSTRACT Using a cell with horizontally mounted membranes, volume flux was measured as a function of gravitational geometry. Water was placed on one side of the membrane. The opposite side of the membrane was exposed to either aqueous glucose solutions, with densities greater than water; or aqueous ethanol, less dense than water; or ethanol—glucose—water solutions. In all cases, the osmotic pressure gradient generated volume flux from water to the solution. No mechanical stirring was used.Experiments were performed first with water above the membrane and the solution below it. They were then repeated with water below and the solution above the membrane. In all cases, volume flux was significantly larger when the denser liquid was above the membrane.Mach—Zehnder interferograms were obtained for the interface region of the water—membrane—0.1 M glucose system, Results show directly that boundary layers are substantially larger and more uniform with the lower-density liquid above the membrane than with the opposite geometry.These experimental findings are interpreted in terms of a convective gravitational instability that reduces boundary layer dimensions and increases volume flux. Following Rayleigh—Tavlor analysis of fluid gravitational stability, a concentration-gradient Rayleigh Number is developed and used in a mathematical model for gravitationally sensitive volume flux.

Research paper thumbnail of Influence of gravitational field on substance transport in gels

Journal of Membrane Science, 2010

This paper presents an investigation of substance transport in an aqueous solution-gel system. In... more This paper presents an investigation of substance transport in an aqueous solution-gel system. In gels, free convection is damped and hydrodynamic instabilities do not occur, so it is possible to determine the influence of gravity on substance transport. With the aid of a laser interferometric method, specific experiments were performed under conditions in which the substance diffuses according to and against the gravitational force. The concentration profiles and the substance flows were calculated on the basis of interference image analysis. Comparison of the results indicates a noticeable influence of gravitational field on passive substance transport. The gravitational field significantly modifies the amount of transported substance and affects the concentration profiles as well as the time evolution of the concentration field.

Research paper thumbnail of Subdiffusive model of substance releasing from a thick membrane

We study both theoretically and experimentally the process of subdiffusive substance releasing fr... more We study both theoretically and experimentally the process of subdiffusive substance releasing from a thick membrane. The theoretical model uses the subdiffusion equation with fractional time derivative and specific boundary conditions at the membrane surfaces. Using a special \textit{ansatz} we find analytical formulas describing the time evolution of concentration profiles and an amount of the substance remains in the membrane.

Research paper thumbnail of We propose a method to extract from experimental data the subdiffusion parameterand subdif- fusion coefficient Dwhich are defined by means of the relation h x2i = 2D

� (1+ �) t � where h x2i denotes a mean square displacement of a random walker starting from x = ... more � (1+ �) t � where h x2i denotes a mean square displacement of a random walker starting from x = 0 at the initial time t = 0. The method exploits a membrane system where a substance of interest is transported in a solvent from one vessel to another across a thin membrane which plays here only an auxiliary role. Using such a system, we experimentally study a diffusion of glucose and sucrose in a gel solvent. We find a fully analytic solution of the fractional subdiffusion equation with the initial and boundary conditions representing the system under study. Confronting the experimental data with the derived formulas, we show a subdiffusive character of the sugar transport in gel solvent. We precisely determine the parameter �, which is smaller than 1, and the subdiffusion coefficient D�.

Research paper thumbnail of Application of Two-Membrane System to Measure Subdiffusion Coefficients

Acta Physica Polonica Series B

Comparing the experimental results to theoretical functions, we estimate the subdiffusion coeffic... more Comparing the experimental results to theoretical functions, we estimate the subdiffusion coefficient of PEG2000 in agarose gel. The experiment was performed with the two-membrane system where thin membranes separated homogeneous solution of PEG2000 for pure solvent at an initial moment. The theoretical function was found by solving analytically the subdiffusion equation.

Research paper thumbnail of Subdiffusion in a Membrane System

The subdiffusion is defined by the relation delimiter < (Delta x)2> ˜ talpha with alpha &lt... more The subdiffusion is defined by the relation delimiter < (Delta x)2> ˜ talpha with alpha < 1. We present a new method of calculating the coefficient alpha , which can be used to obtain it experimentally. The method refers to the time evolution of the thickness of the so-called near-membrane layers.

Research paper thumbnail of Laser interferometric investigation of solute transport through membrane-concentration boundary layer system

Journal of Biological Physics, 2015

We investigate diffusive transport in a membrane system with a horizontally mounted membrane unde... more We investigate diffusive transport in a membrane system with a horizontally mounted membrane under concentration polarization conditions performed by a laser interferometry method. The data obtained from two different theoretical models are compared to the experimental results of the substance flux. In the first model, the membrane is considered as infinitely thin, while in the second one as a wall of finite thickness. The theoretical calculations show sufficient correspondence with the experimental results. On the basis of interferometric measurements, the relative permeability coefficient (ζ s ) for the system, consisting of the membrane and concentration boundary layers, was also obtained. This coefficient reflects the concentration polarization of the membrane system. The obtained results indicate that the coefficient ζ s of the membrane-concentration boundary layer system decreases in time and seems to be independent of the initial concentration of the solute.

Research paper thumbnail of A total internal reflection ellipsometry and atomic force microscopy study of interactions between Proteus mirabilis lipopolysaccharides and antibodies

European Biophysics Journal, 2015

Specific antigen-antibody interactions play a central role in the human immune system. The object... more Specific antigen-antibody interactions play a central role in the human immune system. The objective of this paper is to detect immune complexes using label-free detection techniques, that is, total internal reflection ellipsometry (TIRE) and atomic force microscopy (AFM)-based topography and recognition imaging. Interactions of purified rabbit immunoglobulin G (IgG) antibodies with bacterial endotoxins (Proteus mirabilis S1959 O3 lipopolysaccharides) were studied. Lipopolysaccharide was adsorbed on gold surface for TIRE. In the AFM imaging experiments, LPS was attachment to the PEG linker (AFM tip modification). The mica surface was covered by IgG. In TIRE, the optical parameters Ψ and Δ change when a complex is formed. It was found that even highly structured molecules, such as IgG antibodies (anti-O3 LPS rabbit serum), preserve their specific affinity to their antigens (LPS O3). LPS P. mirabilis O3 response of rabbit serum anti-O3 was also tested by topography and recognition imaging. Both TIRE and AFM techniques were recruited to check for possible detection of antigen-antibody recognition event. The presented data allow for determination of interactions between a variety of biomolecules. In future research, this technique has considerable potential for studying a wide range of antigen-antibody interactions and its use may be extended to other biomacromolecular systems.

Research paper thumbnail of Gravitational effects in a passive transmembrane transport: the flux graviosmotic and gravidiffusive effects in non-electrolytes

Journal of biological physics, 2000

In this paper the classification ofthe gravitational effects in a passive transmembranetransport ... more In this paper the classification ofthe gravitational effects in a passive transmembranetransport is presented. Among these effects there arethe flux and force gravitational effects (fluxgraviosmotic effect, osmotic pressure graviosmoticeffect, flux gravidiffusive effect, osmotic pressuregravidiffusive effect, voltage gravielectric effectand current gravielectric effect). The volume fluxgraviosmotic and solute flux gravidiffusive effectsmodel equations for a single-membrane system areelaborated. These models for binary and ternarynon-electrolyte solutions have been verified using anexperimental data volume and solute fluxes forosmotic-diffusion cell with horizontally mountedmembrane. In the experimental set-up, water was placedon one side of the membrane. The opposite side of themembrane was exposed to binary or ternary solutions ofdensities greater than that of water (aqueous glucoseor glucose-0.2 mole/l aqueous ethanol) and binary andternary solutions of densities larger than that ...

Research paper thumbnail of Thermodynamic model equations for heterogeneous multicomponent non-ionic solution transport in a multimembrane system

Journal of biological physics, 1999

Non-equilibrium thermodynamic model equations for non-ionic and heterogeneous n-component solutio... more Non-equilibrium thermodynamic model equations for non-ionic and heterogeneous n-component solution transport in a m-membrane system are presented. This model is based on two equations. The first one describes the volume transport of the solution and the second the transport of the solute. Definitions of the hydraulic permeability, reflection and diffusive permeability coefficients of the m-membrane system and relations between the coefficients of the m-membrane system and the respective membranes of the system are also given. The validity of this model for binary and ternary solutions was verified, using a double-membrane cell with a horizontally mounted membrane. In the cell, volume and solute fluxes were measured as a function of concentration and gravitational configuration.

Research paper thumbnail of The Investigation of Time-dependent Solute Transport through Horizontally Situated Membrane: The Effect of Configuration Membrane System

Journal of biological physics, 1997

This paper presents an experimental and theoretical investigation ofsolute transport through a ho... more This paper presents an experimental and theoretical investigation ofsolute transport through a horizontally situated membrane. Theexperimental investigation was carried out by the laserinterferometric method in association with a computer system ofinterference image analysis. On the basis of this analysis thicknessof near-membrane layers, solution concentration drops on these layersas well as diffusion fluxes of diluted substance are determined.Different fluxes of the soluble substance are observed depending onthe configuration of the system. The results of the experimental andtheoretical investigation of diffusion fluxes are conformable inrespect of measurement error, with one adjustment parameter, i.e. thesolute partition coefficient.

Research paper thumbnail of Surface modification of PET membrane by ion implantation

Vacuum, 2007

Semicrystalline poly(ethylene terephtalate) (PET) foils were irradiated with N 5+ , O 7+ and C 3+... more Semicrystalline poly(ethylene terephtalate) (PET) foils were irradiated with N 5+ , O 7+ and C 3+ ions. Ions beams of 50 keV N 5+ , 70 keV O 7+ and 30 keV C 3+ were produced from the ECR ion source. The induced effects and wettability of ion-implanted membranes were investigated by means of the Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and by the contactangle methods. FTIR measurements of the virgin and irradiated samples show the scission processes of main chains at the ethylene glycol residue. Various degradation processes known from photochemical degradation were also observed. The AFM observation revealed that the surface topography changes after irradiation. The contact-angle measurements showed that the PET membranes became significantly more hydrophilic after the ion irradiation. r

Research paper thumbnail of Laser interferometric analysis of glucose and sucrose diffusion in agarose gel

General physiology and biophysics, 2014

The paper presents the investigation results of glucose and sucrose diffusion in agarose gel stud... more The paper presents the investigation results of glucose and sucrose diffusion in agarose gel studied with laser interferometry method and the results of fluorescence analysis of the macroscopic gel structure. The diffusion kinetics of these substances released from aqueous solutions of a molar concentration of 0.05 M into the agarose solutions of concentrations of 0.5% and 3% in two gravitational configurations of measuring system was analysed. In the first configuration the solute diffused according, whereas in the second one -opposite to the gravitational force. The diffusion was analysed in the time period between 120 and 2400 s with a time interval of ∆t = 120 s. We observed that the convective instabilities were damped well by the agarose gel, which gives the possibility of the interferometric studies of the diffusive transport for other substances in different gravitational configurations of the system. The time characteristics of glucose and sucrose fluxes in both configurations of the system and the gravitational polarisation coefficient values were obtained. The substantial differences in fluxes of glucose and sucrose diffused according and opposite to the gravitational force were observed. Additionally, we observed the differences between the diffusive fluxes of these substances in both configurations in dependence on the gel solution concentration (which is associated with gel porosity dependent on its concentration) and the kind of diffused substance.

Research paper thumbnail of Effect of concentration boundary layers on passive solute flows in a system of two polymeric membranes positioned in vertical planes

Polimery w medycynie, 2003

The results of studies of influence of concentration boundary layers on passive diffusive transpo... more The results of studies of influence of concentration boundary layers on passive diffusive transport in a double-membrane osmo-diffusive cell, containing a series of two (Ml and M(r)) vertically positioned, flat, microporous and symmetric polymer membranes (Nephrophane and Cellulose IMP-1) are presented in this paper. The membranes separated three compartments (l, m, r) containing binary, heterogeneous and non-ionic solutions (aqueous solutions of glucose or ethanol) or ternary non-electrolyte solutions (glucose solutions in 0.75 mol.l-1 solution of ethanol or ethanol solutions in 0.1 mol.l-1 aqueous solution of glucose). Solution concentrations fulfilled the condition C(k)l > C(k)m > C(k)r. The intermembrane compartment (m) was an infinitesimal solution layer. The volume of the m compartment and the volumes of the external (l and r) compartments fulfilled the condition Vl = Vr approximately 170 Vm. The tests were performed for configurations A and B of a double-membrane osmo-d...