Destruction of Emulsions Stabilized by Precipitates of Zirconium and Tributyl Phosphate Degradation Products

1992 ◽  
Vol 99 (2) ◽  
pp. 235-241 ◽  
Author(s):  
Hiroshi Sugai ◽  
Kenzo Munakata
Keyword(s):  
Tributyl Phosphate ◽  
Degradation Products

scholarly journals Study on cleaning solvents using activated alumina in PUREX process

2011 ◽  
Vol 1 (1) ◽  
pp. 71-74
Author(s):  
Y. Arai ◽  
H. Ogino ◽  
M. Takeuchi ◽  
T. Kase ◽  
Y. Nakajima
Keyword(s):  
Phase Separation ◽  
Tributyl Phosphate ◽  
Spent Nuclear Fuel ◽  
Degradation Products ◽  
Purex Process ◽  
Separation Performance ◽  
Activated Alumina ◽  
Alkali Solutions ◽  
Cleaning Solvents ◽  
Separation Test

Abstract The PUREX process is used to extract uranium and plutonium from dissolved solutions (spent nuclear fuel liquor). The extractant is 30% tributyl phosphate in n-dodecane, which is known to be degradable by radiation and nitric acid. Tributyl phosphate degradation products can generally be washed in alkali solutions like sodium carbonate solution; however, it is more difficult to remove n-dodecane degradation products using this method. A method of cleaning solvents using activated alumina is discussed in this study. A degradation sample of 30% TBP/n-dodecane was prepared by irradiating (1.6 MGy) with a 60Co gamma-source. The degradation products were then qualitatively analyzed using a gas chromatography-mass spectrometer (GC-MS). After being irradiated the solvents were cleaned with activated alumina, and a phase separation test with performed in evaluating the cleaned solvent. This resulted in the discovery of a procedure for the removal of n-dodecane degradation products of dodecanol and dodecanone, with about 70% of the degradation products, and the phase separation performance could be clearly improved through use of activated alumina.

Nonphosphate Degradation Products of Tributyl Phosphate and Their Reactivities in Purex Media under Extreme Conditions

2000 ◽  
Vol 129 (1) ◽  
pp. 93-100 ◽  
Author(s):  
Yoshikazu Tashiro ◽  
Ryuji Kodama ◽  
Hiroshi Sugai ◽  
Katsuhiko Suzuki ◽  
Shingo Matsuoka
Keyword(s):  
Tributyl Phosphate ◽  
Degradation Products ◽  
Extreme Conditions

Emulsions Stabilized by Precipitates of Zirconium and Tributyl Phosphate Degradation Products

1992 ◽  
Vol 98 (2) ◽  
pp. 188-195 ◽  
Author(s):  
Hiroshi Sugai ◽  
Kenzo Munakata ◽  
Shigehiko Miyachi ◽  
Shouzo Yasu
Keyword(s):  
Tributyl Phosphate ◽  
Degradation Products

Collagen degradation products modulate matrix metalloproteinase expression in cultured articular chondrocytes

2005 ◽  
Vol 24 (1) ◽  
pp. 63-70 ◽  
Author(s):  
M. Fichter ◽  
U. Körner ◽  
J. Schömburg ◽  
L. Jennings ◽  
A. A. Cole ◽  
...  
Keyword(s):  
Matrix Metalloproteinase ◽  
Articular Chondrocytes ◽  
Degradation Products ◽  
Collagen Degradation ◽  
Collagen Degradation Products

Structural Studies of Fibrinolysis by Electron and Light Microscopy

1999 ◽  
Vol 82 (08) ◽  
pp. 277-282 ◽  
Author(s):  
Yuri Veklich ◽  
Jean-Philippe Collet ◽  
Charles Francis ◽  
John W. Weisel
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Plasminogen Activator ◽  
Structural Changes ◽  
Molecular Mechanisms ◽  
Degradation Products ◽  
Molecular Model ◽  
Three Dimensional ◽  
Tissue Type ◽  
Type Plasminogen Activator

IntroductionMuch is known about the fibrinolytic system that converts fibrin-bound plasminogen to the active protease, plasmin, using plasminogen activators, such as tissue-type plasminogen activator (t-PA) and urokinase-type plasminogen activator. Plasmin then cleaves fibrin at specific sites and generates soluble fragments, many of which have been characterized, providing the basis for a molecular model of the polypeptide chain degradation.1-3 Soluble degradation products of fibrin have also been characterized by transmission electron microscopy, yielding a model for their structure.4 Moreover, high resolution, three-dimensional structures of certain fibrinogen fragments has provided a wealth of information that may be useful in understanding how various proteins bind to fibrin and the overall process of fibrinolysis (Doolittle, this volume).5,6 Both the rate of fibrinolysis and the structures of soluble derivatives are determined in part by the fibrin network structure itself. Furthermore, the activation of plasminogen by t-PA is accelerated by the conversion of fibrinogen to fibrin, and this reaction is also affected by the structure of the fibrin. For example, clots made of thin fibers have a decreased rate of conversion of plasminogen to plasmin by t-PA, and they generally are lysed more slowly than clots composed of thick fibers.7-9 Under other conditions, however, clots made of thin fibers may be lysed more rapidly.10 In addition, fibrin clots composed of abnormally thin fibers formed from certain dysfibrinogens display decreased plasminogen binding and a lower rate of fibrinolysis.11-13 Therefore, our increasing knowledge of various dysfibrinogenemias will aid our understanding of mechanisms of fibrinolysis (Matsuda, this volume).14,15 To account for these diverse observations and more fully understand the molecular basis of fibrinolysis, more knowledge of the physical changes in the fibrin matrix that precede solubilization is required. In this report, we summarize recent experiments utilizing transmission and scanning electron microscopy and confocal light microscopy to provide information about the structural changes occurring in polymerized fibrin during fibrinolysis. Many of the results of these experiments were unexpected and suggest some aspects of potential molecular mechanisms of fibrinolysis, which will also be described here.

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