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Isotopic exchange of potassium in an illite under equilibrium conditions
Abstrncts amount of cupric ion complexed was decreased, if the ion was added to an oxidizing solution after the initiation of polymerization of the o-quinone type reaction products. The kinetics of the exchange and complexing processes for cupric ions with enzyme and reaction products are discussed mathematically. Bromine-82 Labelling of Human Serum Albumin, Fibrinogen and Insulin by Electrochemical Means.* V. ROSA, G. A. SCASSELLATI and G. PENNISI, SORIN Centro Ricerche Nucleari, Saluggia, Italy The paper gives results obtained with a method using bromine-82 to label human serum albumin, fibrinogen and insulin, three organic substances of special importance in diagnostics and biological research. The method involves electrolytic bromination in an aqueous solution; this is performed in an electrolysis cell, whose anodic zone containing the substance to be labelled is partitioned from the cathodic zone by a dialysis membrane. For each of the three substances mentioned? the degree of bromination produced by a direct current (100,200,300 x 1O-6 A) was studied as a function of anode potential in 10-s and 10d4 M solutions of NH4Br, the amount of bromine-labelled substance formed being checked by radioelectrophoresis for various anodic potential values differing from each other by 50 mV. By immuno-electrophoresis it was ascertained that denaturation of albumin and fibrinogen only starts at anodic potential values for which the degree of labelling is already very high as compared with that yielded by chemical methods of labelling. The method here described has the advantage of rapid execution and is well suited to remote handling in a shielded zone. Isotopic Exchange of Potassium under Equilibrium Conditions.? and G. H. BOLT, Landbowhegeschool, Netherlands
in an Illite M. E. SUMNER Wageningen,
The kinetics of potassium exchange in an illite was studied using K42. In contrast to existing chemical * SM-32/50. t S&<-32/51.
Original Original
: French. : English.
of&qw:r
537
extraction procedures, K42 exchange allows the investigation of the exchange to bc made under equilibrium conditions. Up to the present time few attempts have been made in this direction, because of thr relatively low specific activity of the available K”? isotope (about 10 mC per g of Ii). In combination with the fact that the equilibrium concentration of K in the soil solution is usually less than about IO-” molar, this implies that the observed count rate at the outset of the experiment is of the order of 1000 cpm per ml solution, and thus about 10 cpm per ml after three days of equilibration. If the rate of exchange is to be studied over longer periods, the use of lowbackground counting equipment becomes imperative. Experiments were carried out with a number of samples from the same illite, varying in percentage K-saturation and pretreatment. The results indicate that after a very fast initial exchange (presumably K ions present in surface positions) the subsequent exchange is very slow, and in a number of cases nondetectable within a period of about 8 days. Experience with the Irradiation of Ammonium Bromide. * K. HEYDORN, Forsagsanlaeg Riser, Roskilde, Denmark Irradiation of ammonium bromide with slow neutrons is a routine method for the production of Brsz for many purposes. While the majority of such irradiations are carried out in our thermal column, it was found desirable in some cases to increase the specific activity by irradiating in positions close to the reactor core. During one such irradiation, rupture of the irradiation can occurred, resulting in severe contamination of the irradiation tube and also of the air in the reactor hall. Rupture of the irradiation cans requires 8-10 atmospheres gas pressure, corresponding to a high degree of decomposition of the target material. An investigation of previous irradiations showed that evolution of N,, H,, HBr and Br, had taken place, and an attempt is made to correlate the degree of decomposition with the estimated radiation doses. A rig is being installed shortly, which will permit following the gas-evolution quantitatively as well as qualitatively as a function of radiation dose. * SM-32/52.
Original:
English.
in an Illite M. E. SUMNER Wageningen,
The kinetics of potassium exchange in an illite was studied using K42. In contrast to existing chemical * SM-32/50. t S&<-32/51.
Original Original
: French. : English.
of&qw:r
537
extraction procedures, K42 exchange allows the investigation of the exchange to bc made under equilibrium conditions. Up to the present time few attempts have been made in this direction, because of thr relatively low specific activity of the available K”? isotope (about 10 mC per g of Ii). In combination with the fact that the equilibrium concentration of K in the soil solution is usually less than about IO-” molar, this implies that the observed count rate at the outset of the experiment is of the order of 1000 cpm per ml solution, and thus about 10 cpm per ml after three days of equilibration. If the rate of exchange is to be studied over longer periods, the use of lowbackground counting equipment becomes imperative. Experiments were carried out with a number of samples from the same illite, varying in percentage K-saturation and pretreatment. The results indicate that after a very fast initial exchange (presumably K ions present in surface positions) the subsequent exchange is very slow, and in a number of cases nondetectable within a period of about 8 days. Experience with the Irradiation of Ammonium Bromide. * K. HEYDORN, Forsagsanlaeg Riser, Roskilde, Denmark Irradiation of ammonium bromide with slow neutrons is a routine method for the production of Brsz for many purposes. While the majority of such irradiations are carried out in our thermal column, it was found desirable in some cases to increase the specific activity by irradiating in positions close to the reactor core. During one such irradiation, rupture of the irradiation can occurred, resulting in severe contamination of the irradiation tube and also of the air in the reactor hall. Rupture of the irradiation cans requires 8-10 atmospheres gas pressure, corresponding to a high degree of decomposition of the target material. An investigation of previous irradiations showed that evolution of N,, H,, HBr and Br, had taken place, and an attempt is made to correlate the degree of decomposition with the estimated radiation doses. A rig is being installed shortly, which will permit following the gas-evolution quantitatively as well as qualitatively as a function of radiation dose. * SM-32/52.
Original:
English.