The Influence of Formation Calcium and Magnesium on the Effectiveness of Generically Different Barium Sulphate Oilfield Scale Inhibitors

2003 ◽  
Vol 18 (01) ◽  
pp. 28-44 ◽  
Author(s):  
G.M. Graham ◽  
L.S. Boak ◽  
K.S. Sorbie
Keyword(s):  
Barium Sulphate ◽  
Calcium And Magnesium

Scanning Electron Microscopic and Electrophoretic Observations on Barium Sulphate Used to Adsorb Clotting Factors

1975 ◽  
Vol 33 (02) ◽  
pp. 256-270
Author(s):  
R. M Howell ◽  
S. L. M Deacon
Keyword(s):  
Electron Microscopy ◽  
Factor Xa ◽  
Barium Sulphate ◽  
High Density ◽  
Low Density ◽  
Factor X ◽  
Clotting Factors ◽  
Electron Microscopic ◽  
Complementary Techniques ◽  
Scanning Electron

SummaryElectron microscopy and particle electrophoresis were found to be complementary techniques with which to complete the physical data from an earlier study on barium sulphates used to adsorb clotting factors from serum. The differences revealed by scanning electron microscopy (S. E. M.) in the physical shape of low and high density grades of barium sulphate particles appear to be of greater significance than charge as expressed by electrophoretic mobility, in determining whether or not precursor or preformed factor Xa is eluted.This conclusion was based on the finding that at pH values close to 7, where the adsorption from serum occurs, all samples with the exception of natural barytes were uncharged. However as the high-density, or soil-grade, was found by S. E. M. to consist of large solid crystals it was suggested that this shape might induce activation of factor X as a result of partial denaturation and consequent unfolding of the adsorbed protein. In contrast, uptake of protein into the centre of the porous aggregates revealed by S. E. M. pictures of low-density or X-ray grade barium sulphate may afford protection against denaturation and exposure of the enzyme site.The porous nature of particles of low-density barium sulphate compared with the solid crystalline forms of other grades accounts not only for its lower bulk density but also for its greater surface/gram ratio which is reflected by an ability to adsorb more protein from serum.Neither technique produced evidence from any of the samples to indicate the presence of stabilising agents sometimes used to coat particles in barium meals.

The Effect of Calcium and Magnesium on Rabbit Blood Platelet Aggregation in Vitro

1964 ◽  
Vol 12 (01) ◽  
pp. 179-200 ◽  
Author(s):  
Torstein Hovig
Keyword(s):  
Platelet Aggregation ◽  
Cation Exchange ◽  
Calcium Concentration ◽  
Blood Platelets ◽  
Blood Platelet ◽  
Rabbit Blood ◽  
Calcium And Magnesium ◽  
Induced Aggregation ◽  
Blood Platelet Aggregation

SummaryThe effect of calcium and magnesium on the aggregation of rabbit blood platelets in vitro was studied, with the following results:1. Platelet aggregation induced by ADP or collagen could be prevented by EGTA or EDTA. The aggregating effect was restored by recalcification. The effect was also restored by addition of magnesium in EDTA-PRP, but not in EGTA-PRP unless a surplus of calcium was present.2. Calcium remained in concentrations of the order of 0.15–0.25 mM after dialysis or cation exchange of plasma. Aggregation of washed platelets resuspended in such plasma could not be produced with ADP or collagen, unless the calcium concentration was increased or that magnesium was added.3. The adhesiveness of blood platelets to collagen was reduced in EGTA-PRP and EDTA-PRP. Release of ADP from platelets influenced by collagen could not be demonstrated either in EGTA-PRP (presence of magnesium) or in EDTA-PRP.4. It is concluded that calcium is a necessary factor both for the reaction leading to release of ADP and for the the aggregation produced by ADP.5. Thrombin induced aggregation of washed platelets suspended in tris-buffered saline in the presence of calcium. No effect of magnesium could be observed unless small quantities of calcium were present.

Relationship of Calcium and Magnesium to the Occurrence of Bloat in Lamb

1962 ◽  
Vol 21 (4) ◽  
pp. 798-803 ◽  
Author(s):  
Keith J. Smith ◽  
Walter Woods
Keyword(s):  
Calcium And Magnesium ◽  
Relationship Of

Effect of barium sulphate precipitation in a pressurized environment

2020 ◽  
Author(s):  
Vitória Felicio Dornelas ◽  
Cristiano Severo AIolfi ◽  
Valéria Santos ◽  
Daniel Ribeiro ◽  
Fabio de Assis Ressel Pereira ◽  
...  
Keyword(s):  
Barium Sulphate

Role of kidney in maintaining calcium and magnesium homeostasis and its disorders (Part I)

2018 ◽  
Vol 20 (2) ◽  
pp. 150-169
Author(s):  
Ja.F. Zverev ◽  
◽  
V.M. Bryukhanov ◽  
A.Ya. Rykunova ◽  
◽  
...  
Keyword(s):  
Magnesium Homeostasis ◽  
Calcium And Magnesium

Thermodynamic properties of montechellite

2019 ◽  
Vol 64 (12) ◽  
pp. 1274-1280
Author(s):  
L. P. Ogorodova ◽  
Yu. D. Gritsenko ◽  
M. F. Vigasina ◽  
A. Yu. Bychkov ◽  
D. A. Ksenofontov ◽  
...  
Keyword(s):  
High Temperature ◽  
Gibbs Energy ◽  
Solution Calorimetry ◽  
Thermochemical Study ◽  
Gibbs Energy Of Formation ◽  
Calvet Microcalorimeter ◽  
Magnesium Orthosilicate ◽  
Calcium And Magnesium ◽  
The Enthalpy Of Formation ◽  
Energy Of Formation

A thermochemical study of natural calcium and magnesium orthosilicate ─ monticellite (Ca1.00Mg0.95)[SiO4] (Khabarovsk Territory, Russia) was carried out on the Tian-Calvet microcalorimeter. The enthalpy of formation from the elements fHоel(298.15 K) = -2238.4 4.5 kJ / mol was determined by the method of high-temperature melt solution calorimetry. The enthalpy and Gibbs energy of formation of monticellite of the theoretical composition of CaMg[SiO4] are calculated: fH0el(298.15 K) = -2248.4 4.5 kJ/mol and fG0el(298.15 K) = -2130.5 4.5 kJ/mol.

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