scholarly journals A new dynamic model system for the study of capture reactions for diffusable compounds in cytochemistry. I. Description of the model with special attention to phosphate capture in acid phosphatase cytochemistry.

1978 ◽  
Vol 26 (5) ◽  
pp. 331-339 ◽  
Author(s):  
A S de Jong ◽  
T J Hak ◽  
P van Duijn ◽  
W T Daems
Keyword(s):  
Acid Phosphatase ◽  
Model System ◽  
Phosphate Concentration ◽  
Model Studies ◽  
System A ◽  
Phosphate Ions ◽  
The Matrix ◽  
Phosphatase Cytochemistry ◽  
Trapping Reactions ◽  
Bone Calcification

A model system is described for the investigation of the dynamics of precipitation processes in a matrix. In this system a solution containing the molecular species to be precipitated and the precipitating medium are pumped along opposite sides of a polyacrylamide film. The solutions flowing continuously along the film, interact and can form a precipitate inside the film. The applicability of the model was tested on the capture reaction for phosphate ions by the Gomori type medium for acid phosphatase. Precipitation of lead phosphate in the film occurred only at a phosphate concentration above a certain value. The dependence of this minimal phosphate concentration on various parameters was studied and the results were compared with values found in earlier model studies and calculations concerning phosphate concentrations that can be built up in lysosomes during the Gomori reaction. The system seems promising for obtaining fundamental data about other cytochemical enzyme trapping reactions as well as for the matrix facotrs involved in bone calcification and shell formation.

scholarly journals A NEW METHOD FOR THE INVESTIGATION OF THE CAPTURE REACTION IN PHOSPHATASE CYTOCHEMISTRY III. EFFECTS OF THE COMPOSITION OF THE INCUBATION MEDIUM ON THE TRAPPING OF PHOSPHATE IONS IN A MODEL SYSTEM

1974 ◽  
Vol 22 (2) ◽  
pp. 110-119 ◽  
Author(s):  
C. J. CORNELISSE ◽  
P. VAN DUIJN
Keyword(s):  
Model System ◽  
Chloride Ions ◽  
Trapping Efficiency ◽  
Lead Salt ◽  
Lead Phosphate ◽  
Enzyme Cytochemistry ◽  
Factors Affecting ◽  
Capture Reaction ◽  
Phosphate Ions ◽  
Phosphatase Cytochemistry

A model system developed for the study of diffusion problems in lead salt enzyme cytochemistry served as a basis for the experiments reported in the present paper. Phosphate leakage, which was investigated in polyacrylamide films during incubation in media containing lead, could be expressed by a graphical parameter related to the average displacement of the phosphate ions prior to the onset of lead phosphate precipitation in the films. This parameter can be used as a measure for the efficiency of the capture reaction in cytochemical reactions in tissue sections. The concentration of lead ions, and to a lesser extent that of the phosphate ions, was found to be critical for the degree of phosphate diffusion in this system. Addition of 0.3% of β-glycerophosphate to the lead medium gave increased phosphate diffusion, and trapping was markedly improved by added chloride ions. Raising of the molarity of the acetate buffer resulted in impaired trapping efficiency. Similar findings were made in a parallel study on the kinetics of lead phosphate precipitation in supersaturated solutions with a nephelometric method. The results of the present investigation indicate that the film model system is highly suitable for the study of factors affecting the rapid immobilization of diffusible products of cytochemical reactions.

The use of a silica-based heat sink to “uncouple” the matrix-assisted laser desorption/ionization (MALDI) mechanism

2011 ◽  
Vol 89 (4) ◽  
pp. 446-460 ◽  
Author(s):  
E. Lourantos ◽  
O. M. Ramirez ◽  
A. E. Giannakopulos ◽  
K. A. Beran ◽  
Peter J. Derrick ◽  
...  
Keyword(s):  
Gas Phase ◽  
Heat Sink ◽  
Model System ◽  
Model Systems ◽  
Laser Desorption Ionization ◽  
System A ◽  
The Matrix ◽  
Pass Through ◽  
Maldi Mechanism ◽  
Silicon Based

The relationships between ion yield(s) as a function of desorption alone and (or) ionization was investigated using two model systems. In the first model system, a carbohydrate (2,3,6-tri-O-methyl-β-cyclodextrin, TMBCD), which could be directly laser desorbed, was analyzed with and without a silicon-based heat sink compound (HSC). The HSC allowed heat to pass through but obstructed the flow of charge. In the second model system, a peptide (substance P), which ccould not be laser desorbed, was analyzed under similar conditions. The ion yield of TMBCD under either system of heat conductivity was similar, whereas the ion yield of the peptide with the heat sink was negligible. Compounds that are predominately cationized either in the gas phase or preformed in solution give an ion yield that is not dependent upon the surface conditions, whereas compounds that are not ordinarily cationized are affected by the emission of electrons from the metal surface.

Demonstration of Secondary Lysosomes in Bovine Megakaryocytes and Platelets Using Acid Phosphatase Cytochemistry with Cerium as a Trapping Agent

1990 ◽  
Vol 63 (01) ◽  
pp. 127-132 ◽  
Author(s):  
Michèle Ménard ◽  
Kenneth M Meyers ◽  
David J Prieur
Keyword(s):  
Acid Phosphatase ◽  
Electron Density ◽  
Golgi Complex ◽  
Initial Report ◽  
Cerium Phosphate ◽  
Virtual Absence ◽  
Phosphatase Cytochemistry ◽  
Secondary Lysosomes ◽  
Trapping Agent

SummaryThe ultrastructure of lysosomes from bovine megakaryocytes (MK) and platelets was characterized using acid phosphatase cytochemistry with beta-glycerophosphate as substrate and cerium as a trapping agent. The technique was easily reproducible; cerium-phosphate precipitates were uniform, readily visualized, and there was a virtual absence of nonspecific reaction product. Acid phosphatase was localized in the trans aspect of the Golgi complex and/or granules of less than 50 nm to 650 nm diameters in MK at all stages of maturation. Forty percent of the MK lysosomes contained inclusions of variable shapes, sizes and electron-density and were classified as secondary lysosomes. Twenty-four percent of the platelet sections contained acid phosphatase-positive granules. Fifty-four percent of these were secondary lysosomes. This is the initial report demonstrating secondary lysosomes in either resting MK or platelets using acid phosphatase cytochemistry. These findings suggest that MK and platelet lysosomes have an intracellular function in resting MK and platelets.

scholarly journals The Meaning of the Matrix: Towards a Cybernetic Critical Theory of Capitalism

2018 ◽  
Vol 6 (1) ◽  
pp. 1
Author(s):  
Shay Hershkovitz
Keyword(s):  
Social Systems ◽  
Theoretical Concept ◽  
Social Actors ◽  
System A ◽  
The Social ◽  
Social Entity ◽  
Key Concepts ◽  
The Matrix ◽  
Critical Approaches ◽  
Operational Logic

Marxist criticism is most discernible; despite the oft-repeated claim that it is now irrelevant, belonging to an age now past. This essay assumes that criticism originating in the Marxist school of thought continue to be relevant also in this present time; though it may need to be further developed and improved by integrating newer critical approaches into the classic Marxist discourse. This essay therefore integrates basic Marxist ideas with key concepts from ‘social systems theory’; especially the theory of the German sociologist Niklas Luhmann's. In this light, capitalism is conceptualized here as a ‘super (social) system’: a meaning-creating social entity, in which social actors, behaviors and structures are realized. This theoretical concept and terminology emphasizes the social construction of control and stability, when discussing the operational logic of capitalism.

scholarly journals Pyromorphite formation from montmorillonite adsorbed lead

Mineralogia ◽  
2011 ◽  
Vol 42 (2-3) ◽  
pp. 75-91 ◽  
Author(s):  
Tomasz Bajda ◽  
Tomasz Marchlewski ◽  
Maciej Manecki
Keyword(s):  
Ion Exchange ◽  
Aqueous Solutions ◽  
Phosphate Concentration ◽  
High Concentration ◽  
Exchange Effect ◽  
System A ◽  
New Phase

Pyromorphite formation from montmorillonite adsorbed lead The reaction of Pb-adsorbed montmorillonite with aqueous solutions of PO4 and Cl ions results in the decrease in phosphate concentration associated with the formation of a new phase - pyromorphite Pb5(PO4)3Cl. Pyromorphite crystals range in size from hundreds of nm to several tens of μm, depending on the PO4, K, and Ca concentrations in the reacting system. A strong ion-exchange effect of K+ and Ca2+ cations on desorption of Pb2+ from Pb-adsorbed montmorillonite was observed. Also, a high concentration of cations leads to a rapid desorption of Pb and the formation of fine pyromorphite crystals. In contrast, low PO4, K and Ca concentrations result in the formation of relatively large euhedral crystals. Final Pb concentrations are much lower in experimental sets than in control experiments with no phosphate present.

scholarly journals Acid-beta-glycerophosphatase reaction products in the central nervous system mitochondria following x-ray irradiation.

1975 ◽  
Vol 23 (6) ◽  
pp. 402-410 ◽  
Author(s):  
L Roizin ◽  
D Orlovskaja ◽  
J C Liu ◽  
A L Carsten
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Acid Phosphatase ◽  
Enzyme Reaction ◽  
Reaction Products ◽  
Huntington's Chorea ◽  
X Ray ◽  
System A ◽  
Chemical Lesion ◽  
The Central Nervous System

A survey of the literature to date on the enzyme histochemistry of intracellular organelles has not yielded any reference to the presence of acid phosphatase reaction products in the mammalian mitochondria of the central nervous system. A combination of Gomori's acid phosphatase mehtod, however, with standard electron microscopy has disclosed the presence of enzyme reaction products in the mitochondria of the central nervous system of rats from 2 hr to 22 weeks after x-ray irradiation, as well as in a cerebral biopsy performed on a patient affected by Huntington's chorea. No enzyme reaction products, on the other hand, were observed in serial sections that had been incubated in substrates either containing sodium fluoride or lacking in beta-glycerophosphate. The abnormal mitochondrial enzyme reaction (chemical lesion) is considered to be the consequenco of the pathologic process affecting the ultrastructural-chemical organization of the organelle.

scholarly journals CONSTRUCTION OF MINIMAX CONTROL FOR ALMOST CONSERVATIVE CONTROLLED DYNAMIC SYSTEMS WITH THE LIMITED PERTURBATIONS

2017 ◽  
Vol 2 ◽  
pp. 9-15
Author(s):  
Iryna Svyatovets
Keyword(s):  
Riccati Equation ◽  
Infinite System ◽  
Conservative System ◽  
Coefficient Matrix ◽  
Necessary Condition ◽  
Existence Of A Solution ◽  
Minimax Control ◽  
System Of Matrix Equations ◽  
System A ◽  
The Matrix

The problem is considered for constructing a minimax control for a linear stationary controlled dynamical almost conservative system (a conservative system with a weakly perturbed coefficient matrix) on which an unknown perturbation with bounded energy acts. To find the solution of the Riccati equation, an approach is proposed according to which the matrix-solution is represented as a series expansion in a small parameter and the unknown components of this matrix are determined from an infinite system of matrix equations. A necessary condition for the existence of a solution of the Riccati equation is formulated, as well as theorems on additive operations on definite parametric matrices. A condition is derived for estimating the parameter appearing in the Riccati equation. An example of a solution of the minimax control problem for a gyroscopic system is given. The system of differential equations, which describes the motion of a rotor rotating at a constant angular velocity, is chosen as the basis.

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