Wyniki wyszukiwania - Biblioteka Nauki

1

Studies on Transport of Pb(II) Ions Using Different Crown Ethers

100%

Ashraf W. , Fazal A.

Polish Journal of Chemistry

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2006

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tom Vol. 80, nr 6

881-887

EN

Membrane based separation processes represent a sophisticated way to limit industrial wastes in the natural environment. Crown ethers have been recognized as very effective class of compounds to achieve selective separation of heavy metal ions from aqueous solutions. Lead (Pb) is a well known toxic metal and is heavily used in industry. Therefore, finding ways to selectively remove Pb(II) from aqueous solutions is important. In the present paper, different crown ethers of varying cavity size, subsituent groups, donor atoms, and ring number are compared for their ability to transport Pb2+ through a supported liquid membrane. All experiments were carried out in a laboratory scale membrane reactor with crown ether solution immobilized on a polypropylene porous sheet interposed between feed and strip solutions. It was observed that when O atoms of the same sized macrocycle are replaced with N or S atoms, percentage recovery of Pb(II) increases significantly. By substituting a benzene ring on the same sized macrocycle, the percentage of Pb(II) transport increased from 78 to 86%. The cavity size of the crown ether seems to affect the rate of transport. After different trials, it was found that transport is maximal where the ionic radius of Pb(II) matches maximum with the cavity diameter of the macrocycle. These interactions of crown ethers with Pb(II) are explained on the basis of metal-ligand coordination chemistry.

2

Complexes of valinomycin-Kplus and FFAs as proton carriers across lipid membranes

100%

Fogt A.

Cellular and Molecular Biology Letters

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2002

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tom 07

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nr Suppl.

3

Practical Kedem-Katchalsky equations and their modification

88%

Jarzyńska M.

Open Physics

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2007

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tom 5

|

nr 4

586-598

EN

The research problem presented in this work concerns modification of the Kedem-Katchalsky (K-K) equation for volume flow (J v) through system (h|M|l), consisting of a membrane M and boundary layers h and l. Such boundary layers appear in the vicinity of the membrane on both sides due to the lack of mixing of solutions. This paper also includes the derivation of the equation for volume flow (J vr) dissipated on concentration boundary layers h and l. The derivation of these equations concerns the case in which the substance transport through the membrane is generated by the osmotic pressure gradient $$\Delta \dot \prod $$ . On the basis of the equations for the volume flows (J v) and (J vr), some calculations for a nephrophane membrane, used in medicine, and for aqueous glucose solutions have been carried out. In order to test the equations for (J v) and (J vr), we have also carried out calculations for the volume flow (J′ v) that is transferred through the membrane in the case of mixed solutions on both sides of the membrane. This volume flux has been calculated on the basis of the original (K-K) equation. The results are presented in Fig. 2.

4

A nonlinear dynamic systems theory approach to biological potential oscillations

88%

Buchete N. V. , Dasu A. , Andricioaei I. , Frangopol P. T.

Biophysics of Membrane Transport

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1994

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tom 12

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nr 2

5

Membrane transport of glutathione conjugates

88%

Bartosz G.

Current Topics in Biophysics

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1994

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tom 18

|

nr 2

6

Concentration dependencies of the Pij Peusner coeffcient for the non-electrolyte ternary solutions

75%

JASIK-ŚLĘZAK J. , WĄSIK S. , ŚLĘZAK A.

Acta Scientifica Academiae Ostroviensis. Sectio A, Nauki Humanistyczne, Społeczne i Techniczne

|

2016

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nr 7(1)/2016

252-263

EN

Peusner’s Network Thermodynamics belongs to a group of modern thermodynamics. It provides a convenient research framework for membrane transports. One of the many research tools to study membrane transport are Kedem-Katchalsky equations. A network forms of hybrid Kedem-Katchalsky equations (K-K) for ternary non-electrolyte solutions may contain one of the six Peusner coefficients i.e. Hij, Wij, Nij, Kij, Sij or Pij (i, j  {1, 2, 3}) that form third-order matrices of the Peusner coefficients i.e. [H], [W], [N], [K], [S] or [P]. Aim of this study was to calculation of family of dependencies of Peusner coefficients Pij (i, j  {1, 2, 3}) on average concentration of a homogeneous solution of one component in a membrane (C ̅_1) for several different values of the second component (C ̅_2). Calculations were made for aqueous glucose and ethanol solutions and membrane with transport parameters Lp, σ and ω on the basis of network K-K equations for ternary solutions of non-electrolytes that contain the coefficient Pij. It has been shown that the Pij are non-linearly (hyperbolic) dependent on solutions concentrations C ̅_1 and C ̅_2. Non-linearity of coefficients Pij results from the properties of mathematical equations describing them.

PL

Termodynamika sieciowa Peusnera należy do grupy termodynamiki współczesnej. Stanowi ona wygodne ramy badawcze transportów membranowych. Jednym z wielu narzędzi badawczych transportu membranowego są równania Kedem - Katchalsky’ego. Sieciowe postaci hybrydowych równań Kedem-Katchalsky’ego (K-K) dla ternarnych roztworów nieelektrolitowych mogą zwierać jeden z sześciu współczynników Peusnera: Hij, Wij, Nij, Kij, Sij lub Pij (i, j  {1, 2, 3}), tworzących macierze trzeciego stopnia współczynników Peusnera [H], [W], [N], [K], [S] lub [P]. Celem pracy było obliczenie rodziny zależności współczynników Peusnera Pij (i, j  {1, 2, 3}), od średniego stężenia jednego składnika jednorodnego roztworu w membranie (C ̅_1) dla kilku różnych, ustalonych wartości drugiego składnika (C ̅_2). Analizowano transport wodnych roztworów glukozy i etanolu przez membranę o parametrach transportowych Lp, σ i ω, przy pomocy sieciowych równań K-K dla ternarnych roztworów nieelektrolitów, zawierających współczynnik Peusnera Pij. Stwierdzono, że współczynniki Pij są nieliniowo (hiperbolicznie) zależne od stężeń C ̅_1 i C ̅_2. Nieliniowość owych współczynników wynika z właściwości równań matematycznych opisujących współczynniki Pij.

7

Derivation of the formula for the filtration coefficient by application of Poiseuille's law in membrane transport

75%

Jarzynska M. , Pietruszka M.

Acta Societatis Botanicorum Poloniae

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2009

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tom 78

|

nr 2

93-96

EN

On the basis of Kedem-Katchalsky equations a mathematical analysis of volume flow (Jv) of a binary solution through a membrane (M) is presented. Two cases of transport generators have been considered: hydrostatic (Δp) as well as osmotic (Δπ) pressure difference. Based on the Poiseuille's law we derive the formula for the membrane filtration coefficient (Lp) which takes into account the membrane properties, kinetic viscosity and density of a solution flowing across the membrane. With use of this formula we have made model calculations of the filtration coefficient Lp and volume flow Jv for a polymer membrane in the case when the solutions on both sides of the membrane are mixed.

8

Translocation of polysialic acid across model membranes: Kinetic analysis and dynamic.

75%

Janas T. , Krajiński H. , Timoszyk A. , Janas T.

Acta Biochimica Polonica

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2001

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tom 48

|

nr 1

163-173

EN

Transmembrane translocation of polyion homopolymers takes place in the case of polyanionic polysialic acid (polySia), polyanionic polynucleotides and polycationic polypeptides. The purpose of this work was to determine the role of membrane electrical parameters on the kinetics of polyion translocation, the influence of polysialic acid on ion adsorption on positively charged membrane surface and the dynamics of the phospholipid hydrocarbon chains and choline group by using 1H-NMR. The analysis of polyion translocation was performed by using the electrical equivalent circuit of the membrane for the initial membrane potential equal to zero. The changes in polysialic acid flux was up to 75% after 1 ms in comparison with the zero-time flux. Both a decrease of membrane conductance and an increase of polyion chain length resulted in the diminution of this effect. An increase of praseodymium ions adsorption to positively charged liposomes and an increase of the rate of segmental movement of the -CH2 and -CH3 groups, and the choline headgrup of lipid molecules, was observed in the presence of polySia. The results show that the direction of the vectorial polyion translocation depends both on the membrane electrical properties and the degree of polymerization of the polymer, and that polysialic acid can modulate the degree of ion adsorption and the dynamics of membrane lipids.

9

Model equation of relative solute permeability coefficient of membrane-concentration boundary layers complex

75%

Bryll A. , Michalska-Małecka K. , Grzegorczyn S. , Ślęzak A.

Polimery

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2009

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tom T. 54, nr 9

662-667

EN

Considering non-homogeneity of non-electrolyte solutions, the membrane transport is different than the transport of homogeneous solutions described by Kedem-Katchalsky equations, as a result of the concentration polarization phenomenon and concentration boundary layers formed up near the membrane. These layers have a significant influence on the volume and solution flows. The model equation for the relative permeability coefficient ?s of the system: the membrane and concentration boundary layers is presented, and dependence of this coefficient on the solution concentration, concentration Rayleigh number, and gravity acceleration is studied. The experimental tests were performed by a chamber system method in the membrane system with the membrane mounted horizontally. The test results show a good compliance with theoretical calculations and indicate that the relative solute permeability coefficient of the membrane-concentration boundary layers system decreases in time and seems to be independent on the initial concentration of the solution.

PL

Szerokie zastosowanie membran polimerowych w technologii i naukach medycznych, niesie ze sobą konieczność ich szczegółowego badania pod kątem właściwości transportowych. Ze względu na niejednorodność roztworów nieelektrolitów, ich transport membranowy różni się od transportu roztworów jednorodnych (opisanych równaniami Kedem-Katchalsky'ego) na skutek zjawiska polaryzacji stężeniowej i tworzenia się przy membranie stężeniowych warstw granicznych. Warstwy te mają znaczący wpływ na przepływy objętościowe i przepływy solutu. Przedstawiono model opisujący względny współczynnik przepuszczalności (?s) w układzie membrana-stężeniowe warstwy graniczne oraz zbadano zależności tego współczynnika od stężenia roztworu, stężeniowej liczby Rayleigha i przyspieszenia grawitacyjnego. Poprawność modelu zbadano eksperymentalnie używając poziomo ustawionej membrany (Nephrophan wykorzystywanej w hemodializerze zwojowym) rozdzielającej przestrzenie układu membranowego. Wyniki badań są zgodne z obliczeniami teoretycznymi i wskazują, że względny współczynnik przepuszczalności solutu w układzie membrana-stężeniowe warstwy graniczne zmniejsza się w czasie i wydaje się być niezależny od początkowego stężenia roztworu.

10

Characteristics of polymeric ultrafiltration membranes produced with the use of graphene oxide

75%

Tomczak E. , Blus M.

Ecological Chemistry and Engineering. S

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2018

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tom Vol. 25, nr 3

419--429

EN

This article describes a method for producing polymeric membranes by adding carbon nanostructures in the form of graphene oxide (GO). The reference membrane (having typical composition) was formed via phase inversion, using polyvinylidene fluoride (PVDF) dissolved in dimethylacetamide (DMAC). The polymeric matrix was additionally enriched with a plasticizer, i.e. polyethylene glycol (PEG). Afterwards, graphene oxide ultrasonically dispersed in dimethylacetamide was added to basic matrix. The membranes were further compared with one another by measuring their contact angle and hydrodynamics. The results were compared with the literature reports. The transport properties of the membranes were assessed with experimental ultrafiltration equipment (KOCH Membrane System). Also, their permeate flux and mass transfer resistance were determined.

11

Ciśnieniowy efekt stężeniowych warstw granicznych w jednomembranowej komórce osmotyczno-dyfuzyjnej

75%

Ślęzak A. , Wąsik J.

Prace Naukowe. Chemia / Wyższa Szkoła Pedagogiczna w Częstochowie

|

2003

|

tom Vol. 8

121--134

PL

Przedstawiono klasyfikację i definicje efektów stężeniowych warstw granicznych w biernym transporcie membranowym. Wyróżniono strumieniowe (strumieniowy efekt stężeniowych warstw granicznych, strumieniowy efekt grawidyfuzyjny, prądowy efekt grawielektryczny) i bodźcowe (ciśnieniowy efekt grawiosmotyczny, ciśnieniowy efekt grawidyfuzyjny, napięciowy efekt grawielektryczny) efekty grawitacyjne. Opracowano matematyczny model ciśnieniowego efektu stężeniowych warstw granicznych w 1-membranowej komórce osmotyczno-dyfuzyjnej zawierającej ustawioną poziomo płaską, mikroporowatą i symetryczną membranę polimerową (Nephrophane) rozdzielającą wodę i dwuskładnikowe (wodne roztwory glukozy) lub trójskładnikowe (roztwory glukozy w 0.2 mol.l-1 wodnym roztworze etanolu) roztwory nieelektrolitów. Obliczenia ciśnieniowego efektu stężeniowych warstw granicznych wykonano dla dwu konfiguracji (A i B) 1-membranowej komórki osmotyczno-dyfuzyjnej. W konfiguracji A roztwór znajdował się pod membraną, natomiast w konfiguracji B - nad membraną. Ponadto zdefiniowano i obliczono ciśnieniowy efekt grawiosmotyczny. Otrzymane rezultaty obliczeń zinterpretowano w kategoriach konwekcyjnej niestabilności, zwiększającej wartość współczynnika przepuszczalności dyfuzyjnej układu: warstwa graniczna/membrana/warstwa graniczna.

12

Transport studies of inorganic and organic cations across liquid membranes containing Mannich-base calix[4]resorcinarenes

63%

Pietraszkiewicz O. , Kozbiał M. , Pietraszkiewicz M.

Polish Journal of Chemistry

|

1998

|

tom Vol. 72, nr 5

886-892

EN

Three calix[4]resorcinarenes, two of them incorporating Mannich-type amino functions (C2 and C3), have been studied in respect to their ionoselectivities towards inorganic alkali cations as well as for organic primary ammonium cations, by ion transport across the bulk liquid membrane and extraction experiments. The ligand C3 displayed particular ionoselectivity for lithium ion, as a carrier in toluene membrane. The discrimination of organic primary ammonium ions was remarkable in liquid membranes, and the pattern of this discrimination depended on the membrane composition. Selectivities for both inorganic and organic ions depended significantly on the membane composition, the substituent in the calix[4]resorcinarene, and the counterion present in the salts studied.

13

Expression of anion exchanger 3 influences respiratory rate in awake and isofurane anesthetized mice

63%

Meier S. , Hubner C. A. , Groeben H. , Peters J. , Bingmann D. , Wiemann M.

Journal of Physiology and Pharmacology. Supplement

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2007

|

tom 58

|

nr 5

14

Sphingosine modulates Ca2 signals via phospholipase C dependent pathway in glioma C6 cells

63%

Czajkowski R. , Sabala P. , Baranska J.

Acta Neurobiologiae Experimentalis

|

1997

|

tom 57

|

nr 4

15

Biological versus synthetic membranes transport

63%

Grzywna Z. J. , Simon A. M. , Siwy Z.

Biophysics of Membrane Transport

|

1994

|

tom 12

|

nr 1

16

Interaction of sulfhydryl reagents with K transport in adrenal chromaffin granules

63%

Szewczyk A. , Lobanov N. A. , Nowotny M. , Nalecz M. J.

Acta Neurobiologiae Experimentalis

|

1997

|

tom 57

|

nr 4

17

Translocation of polysialic acid across model membranes: Kinetic analysis and dynamic studies

63%

Janas T. , Krajinski H. , Timoszyk A. , Janas T.

Acta Biochimica Polonica

|

2001

|

tom 48

|

nr 1

EN

Transmembrane translocation of polyion homopolymers takes place in the case of polyanionic polysialic acid (polySia), polyanionic polynucleotides and polycationic polypeptides. The purpose of this work was to determine the role of membrane electrical parameters on the kinetics of polyion translocation, the influence of polysialic acid on ion adsorption on positively charged membrane surface and the dynamics of the phospholipid hydrocarbon chains and choline group by using 1H-NMR. The analysis of polyion translocation was performed by using the electrical equivalent circuit of the membrane for the initial membrane potential equal to zero. The changes in polysialic acid flux was up to 75% after 1 ms in comparison with the zero-time flux. Both a decrease of membrane conductance and an increase of polyion chain length resulted in the diminution of this effect. An increase of praseodymium ions adsorption to positively charged liposomes and an increase of the rate of segmental movement of the -CH2 and -CH3 groups, and the choline headgrup of lipid molecules, was observed in the presence of polySia. The results show that the direction of the vectorial polyion translocation depends both on the membrane electrical properties and the degree of polymerization of the polymer, and that polysialic acid can modulate the degree of ion adsorption and the dynamics of membrane lipids.

18

Hiring cell gatekeepers – ABC transporters in plant biotechnology

51%

Szewczak A. , Ziomkiewicz I. , Jasinski M.

BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology

|

2011

|

tom 92

|

nr 2

19

GĘSTOŚCIOWE CHARAKTERYSTYKI I RÓWNANIE MODELOWE STRUMIENIA GRAWIOSMOTYCZNEGO

51%

Ślęzak A. , Jasik-Ślęzak J.

Acta Scientifica Academiae Ostroviensis. Sectio A, Nauki Humanistyczne, Społeczne i Techniczne

|

2018

|

nr 12(2)/2018

275-287

PL

Przedstawiono gęstościowe charakterystyki strumienia grawiosmotycznego oraz model matematyczny owego strumienia, opracowany na podstawie formalizmu Kedem-Katchalsky’ego. Korzystając z otrzymanych równań, wykonano obliczenia dla układu dwóch membran z octanu celulozy (Nephrophan) oraz wodnych roztworów KCl i amoniaku. Otrzymane wyniki badań wskazują, że układ dwumembranowy zawierający w przedziale międzymemranowym roztwór ternary o gęstości równej gęstości wody znajdującej się w przedziałach zewnętrznych, może spełniać rolę grawireceptora.

EN

Density characteristics of the graviosmotic flux and the mathematical model of this flux, developed on the basis of Kedem-Katchalsky formalism are presented. Using this equation, calculations were made for a system of two membranes of cellulose acetate (Nephrophan) and aqueous solutions of KCl and ammonia. The obtained results in-dicate that the double-membrane system containing in the central compartment a ter-nary solution with a density equal to the density of water in the external compartments, can act as a gravitceptor.

20

Impact of solute exchange between erythrocytes and plasma on hemodialyzer clearance

51%

Waniewski J. , Poleszczuk J. , Pietribiasi M. , Debowska M. , Wojcik-Zaluska A. , Zaluska W.

Biocybernetics and Biomedical Engineering

|

2020

|

tom Vol. 40, no. 1

265--276

EN

The standard theory of mass transport in dialyzer for water solutions was extended for solutes distributed in both plasma (PW) and erythrocyte intracellular (EW) water. Blood flow was divided into two separate flows of PW and EW with the diffusive exchange of solutes across cellular membrane (CM). Diffusive permeability of CM for urea and creatinine were assumed according to literature data. Computer simulations based on partial differential equations demonstrated that urea diffuses fast across CM and can be approximately considered as distributed uniformly in both blood flow components. In contrast, creatinine can be considered as distributed only in PW flow during the passage along the dialyzer. Therefore, the traditional formula for dialyzer clearance can be applied for urea and creatinine with the adjustment of their effective ‘‘blood’’ flow, but not for solutes with intermediate molecular mass. In vivo clearances of urea and creatinine were, as expected, lower than the respective theoretical predictions based of the diffusive permeability, P, times membrane surface area, A, parameters, PA, for dialyzer membrane, estimated for water solutions, by 33.6 ± 10.9% for creatinine and 10.8 ± 9.4% for urea. The estimated in vivo PAs were for creatinine 65.4 ± 26.0% and for urea 32.0 ± 10.9% lower than in vitro values provided by manufacturers. The much higher drop in clinical clearance/PA for creatinine than for urea suggests that the exchange of creatinine between plasma and dialysis fluid needs to be adjusted for the reduction of the dialyzer membrane surface area, which is effectively available for creatinine, caused by the presence of erythrocytes.