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1

Fluidized bed drying of adhesive particles

100%
Penicka M., Hoffman P., Fort I.
Inżynieria Przetwórstwa Spożywczego
|
2013
|
nr 2
2
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Content available

The molecular mechanism of nondegranulative release of biogenic amines

100%
Uvnas B.
Journal of Physiology and Pharmacology
|
1991
|
tom 42
|
nr 2
According to current teaching biogenic amines are released by exocytos- is, i. e. by evacuation of amine storing vesicles or granules into the extracellular space. The release of transmitter amines is quantal, i. e. occurs in packs of transmitter molecules. These packs are assumed to be identical with vesicle contents, in other words, the smallest releasable quantum equals the amine content of one vesicle. However, there are experimental observations which do not fit in with this version of an exocytotic release theory. Observed quantitative discrepancies could be explained if the release mechanism allowed a fractional release of transmitter amine from several vesicles instead of the total evacuation of a few. The lack of adequate knowledge about the mechanisms of storage of biogenic amines within the vesicles has up til now rendered it difficult to envisage the machinery behind a fractional release of the amine content of a vesicle. In extensive in-vitro studies we have found that the matrices of amine storing granules (i. e. from mast cells, chromaffin cells and nerve terminals) show the properties of weak cation exchanger materials, carboxyl groups serving as amine binding ionic sites. When exposed to cations like sodium and potassium ions, the amines are released from their storage sites according to kinetics characteristic of weak cation exchangers. In vivo, amine release from cat adrenals on splanchnic nerve stimulation also occurs according to ion echange kinetics. Histamine release from mast cells is considered to occur as the result of degranulation, i. e. the expulsion of histamine storing granules to the extracellular space, a typical example of exocytosis. The granules are assumed to loose their histamine by ion exchange, Na⁺ Hi⁺, on exposure to the sodium-rich extracellular medium. However, recent observations on histamine release from superfused mast cells suggest that the release of histamine, although caused by ion exchange, is due to intracellular ion exchange at granule sites between cytoplasmic potassium and activated mast cells as the consequence of intracellular potassium ion flux across the histamine carrying granules, degranulation and extracellular histamine release from expelled granules occurring only as the result of more extensive activation. The possibility of potassium ions being involved also in an ion exchange process behind the release of other biogenic amines e. g. at nerve terminals will be proposed. The amine release will still be quantal but the size of the released quanta will not depend on the total amine content of a vesicle but on the size of the fractions thereof being released, thereby explaining many of the quantitative discrepancies attached to the current exocytotic release theory. A fractional release theory may have interesting consequences for our thinking as to the physiology and pharmacology of processes involving storage and release of biogenic amines.
3

Influence of amphiphilic anionic and cationic mixture on calcium ion desorption from lipid membranes. I. Experiments with small unilamellar vesicles

100%
Fogt A., Kubica K., Kuczera J.
Polish Journal of Environmental Studies
|
1994
|
tom 03
|
nr 4
This paper studies the influence of equimolar mixtures of biologically-active cationic and anionic amphiphiles (dodecyl-oxymethylene-methyl-morpholinium chloride (DOMM) and one of the series of sodium alkylsulphonates (ASJ with n = 1,2,4,6,8,10,12 and 14 carbon atoms in the alkyl chain) on calcium ion desorption from lecithin liposome membranes. It was shown that by choosing the hydrophobic part of the amphiphilic anion in the mixture one can regulate the efficiency of the amphiphilic cation towards the desorption process. The rate constant of that process strongly depends on the surfactant concentration. The differences in the effectiveness of the different compounds are most distinct at lower concentrations and vanish when the concentration increases. The results are discussed in response to the amphiphilic ion-pair hydrophobicity and their electrical properties. The role of the hypothetical, temporal complexes consisting of the alkylsulphonate anion(s) and calcium cation (ASn-Ca)+ in the calcium ion exchange is discussed. The mechanism of Ca2+ desorption from the surface of the phospholipid bilayer under the simultaneous action of the cationic and anionic detergents is proposed. According to our proposal calcium ion release occurs due to the joint action of the monovalent cationic and anionic detergents in coincidence with a divalent calcium ion. To authenticate the proposed mechanisms of calcium ion release, the shapes of the experimental curves were compared with the theoretical ones obtained by computer simulation using the cellular automata method.
4

Biosorption of Cr[III] ions by wheat straw and grass: a systematic characterization of new biosorbents

100%
Chojnacka K.
Polish Journal of Environmental Studies
|
2006
|
tom 15
|
nr 6
Recently, increased interest in the application of various biosorbents in metal ions removal has been observed. The paper presents a systematic characterization of new and commonly abundant low-cost bio- sorbents: above-ground plant parts of wheat straw and grass. Cr(III) was chosen as a model sorbate. The effect of the most significant process parameters (temperature, pH, initial concentration of Cr(III) ions on kinetics, as well as temperature and pH) on biosorption equilibrium was studied. Biosorption was found to be a quick process. The equilibrium was reached within 10-20 minutes. Biosorption capacity of the studied sorbents was intermediate when compared with other sorbents of plant origin ca. 20 mg/g, but since these materials are commonly abundant and of minimal cost, it is possible to improve wastewater treatment ef­ficiency by increasing the concentration of the sorbent. The kinetics of the process in the case of both biomaterials was described with pseudo-second order equation and the equilibrium of biosorption by wheat straw was described with the Freundlich equation and by grass with the Langmuir model. The above equations were chosen to achieve the best consistency of experimental data with the model results. Also, the mechanism of biosorption was investigated, and was determined to be physical adsorption. The paper also discusses the possible methods of utilization of metal-laden biomass, including non-de­structive elution with the regeneration of the biosorbent and ashing as the method of destruction and further concentration of metal.
5

Właściwości jonowymienne ścianki komórki buraka cukrowego

84%
Gazeta Cukrownicza
|
1988
|
tom 96
|
nr 06
6

Immunohistochemical analysis of connexin 26 and 43 expression in the mouse alimentary tract

84%
Fiertak A., Semik D., Kilarski W. M.
Folia Biologica
|
1999
|
tom 47
|
nr 1-2
7

Sorption of iodide on the surface of modified clinoptilolite

84%
Chmielewska-Horvathova E., Lesny J.
Polish Journal of Environmental Studies
|
1996
|
tom 05
|
nr 2
The possibility of using the monoionic Ag+ - form of clinoptilolite of domestic origin for radioactive iodide separation from waters has heen studied. The capacity of the silver form of clinoptilolite towards iodide exceeds many times that of the capacity of clinoptilolite in natural form. Due to low solubility the product Agl iodides generate precipitates on the surface of zeolite. SEM and rtg analyses of the silver form of clinoptilolite after sorption of iodide demonstrate the formation of new crystals on the zeolite surface. In comparison to the origin clinoptilolite sample, TG - analyses show that maximum water release occurs earlier. Sorption of iodide on the silver form of clinoptilolite was described as a second order reaction. The influence of interfering anions on the adsorption capacity of silver clinoptilolite towards iodide was also investigated.
8

The influence of resin regeneration on nitrates removal effectivity from drinking water

84%
Cyplik P., Czaczyk K., Piotrowska-Cyplik A., Marecik R., Grajek W.
Nauka Przyroda Technologie. Uniwersytet Przyrodniczy w Poznaniu
|
2008
|
tom 02
|
nr 1
9

Purification and characterization of extracellular Pseudomonas aeruginosa urate oxidase enzyme

84%
Saeed H. M., Abdel-Fattahyousry Y. R., Gohar M., Elbaz M. A.
Polish Journal of Microbiology
|
2004
|
tom 53
|
nr 1
Urate oxidase (uricase) was isolated and purified from Pseudomonas aeruginosa to apparent homogeneity using ammonium sulphate precipitation followed by ion exchange and gel filtration chromatography. The specific activity of the purified uricase enzyme was found to be 636.36 with the use of uric acid as a substrate. The purified uricase enzyme is a monomeric protein with molecular weight of 64 kilodaltons. The optimal pH and temperature of the purified enzyme is 9.0 and 30°C, respectively. The effect of some metal ions was studied. Sulphate forms of Fe⁺², Zn⁺² and Co⁺² inhibit the uricolytic activity whereas; NaCl and CaCl₂ enhance the enzyme activity. Moreover, the purified enzyme is inhibited by EDTA and KCN.
10

Rozwój bezściekowych procesów jonowymiany w przemyśle cukrowniczym

67%
Schick R., Bohn K.
Gazeta Cukrownicza
|
1988
|
tom 96
|
nr 06
11

Nowe rozwiązania technologiczne dla cukrownictwa

67%
Herve D.
Gazeta Cukrownicza
|
1988
|
tom 96
|
nr 07
12
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Content available

Zastosowanie Amberlitu IRA-400 do rozdzielania wapnia i fosforu w produktach spożywczych pochodzenia roslinnego

59%
Chojnicka B.
Roczniki Państwowego Zakładu Higieny
|
1962
|
tom 13
|
nr 3
13

The balance equation for chemically active substances flowing through porous materials

59%
Slawomirski M. R.
Bulletin of the Polish Academy of Sciences. Earth Sciences
|
2002
|
tom 50
|
nr 1
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