Comparative Labelling and Biokinetic Studies of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn)

1977 ◽  
Vol 16 (01) ◽  
pp. 30-35 ◽  
Author(s):  
N. Agha ◽  
R. B. R. Persson
Keyword(s):  
Complex Formation ◽  
Significant Influence ◽  
Room Temperature ◽  
Ph Value ◽  
Maximum Activity ◽  
Reduction Step ◽  
Labelling Yield ◽  
Different Temperatures ◽  
Kinetics Of

SummaryGelchromatography column scanning has been used to study the fractions of 99mTc-pertechnetate, 99mTcchelate and reduced hydrolyzed 99mTc in preparations of 99mTc-EDTA(Sn) and 99mTc-DTPA(Sn). The labelling yield of 99mTc-EDTA(Sn) chelate was as high as 90—95% when 100 μmol EDTA · H4 and 0.5 (Amol SnCl2 was incubated with 10 ml 99mTceluate for 30—60 min at room temperature. The study of the influence of the pH-value on the fraction of 99mTc-EDTA shows that pH 2.8—2.9 gave the best labelling yield. In a comparative study of the labelling kinetics of 99mTc-EDTA(Sn) and 99mTc- DTPA(Sn) at different temperatures (7, 22 and 37°C), no significant influence on the reduction step was found. The rate constant for complex formation, however, increased more rapidly with increased temperature for 99mTc-DTPA(Sn). At room temperature only a few minutes was required to achieve a high labelling yield with 99mTc-DTPA(Sn) whereas about 60 min was required for 99mTc-EDTA(Sn). Comparative biokinetic studies in rabbits showed that the maximum activity in kidneys is achieved after 12 min with 99mTc-EDTA(Sn) but already after 6 min with 99mTc-DTPA(Sn). The long-term disappearance of 99mTc-DTPA(Sn) from the kidneys is about five times faster than that for 99mTc-EDTA(Sn).

scholarly journals Thermodynamic and detailed kinetic study of the formation of orthophthalaldehyde-agmatine complex by fluorescence intensities

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Khémesse Kital ◽  
Moumouny Traoré ◽  
Diégane Sarr ◽  
Moussa Mbaye ◽  
Mame Diabou Gaye Seye ◽  
...  
Keyword(s):  
Complex Formation ◽  
Thermodynamic Parameters ◽  
Initial Rate ◽  
Reaction Medium ◽  
Standard Entropy ◽  
Step Size ◽  
Formation Reaction ◽  
Different Temperatures ◽  
Kinetics Of ◽  
Complex Formation Process

Abstract The aim of this work is to determine the thermodynamic parameters and the kinetics of complex formation between orthophthalaldehyde (OPA) and agmatine (AGM) in an alkaline medium (pH 13). Firstly, the association constant (Ka) between orthophthalaldehyde and agmatine was determined at different temperatures (between 298 K and 338 K) with a step size of 10 K. Secondly, the thermodynamic parameters such as standard enthalpy (ΔH°), standard entropy (ΔS°),and Gibbs energy (∆G) were calculated, where a positive value of ΔH° (+45.50 kJ/mol) was found, which shows that the reaction is endothermic. In addition, the low value of ΔS°(+0.24 kJ/mol) indicates a slight increase in the disorder in the reaction medium. Furthermore, the negative values of ΔG between −35.62 kJ/mol and −26.02 kJ/mol show that the complex formation process is spontaneous. Finally, the parameters of the kinetics of the reaction between OPA and AGM were determined as follows: when the initial concentration of AGM (5 × 10−6 M) is equal to that of the OPA, the results show that the reaction follows an overall 1.5 order kinetics with an initial rate of 5.1 × 10−7Mmin−1 and a half-life of 8.12 min. The partial order found in relation to the AGM is 0.8. This work shows that the excess of OPA accelerates the formation reaction of the complex.

scholarly journals Influence of Rolling Temperature on the Perfection Degree of Recrystallization Cube Texture in Nickel

2001 ◽  
Vol 35 (1) ◽  
pp. 1-22 ◽  
Author(s):  
B. K. Sokolov ◽  
I. V. Gervasyeva ◽  
D. P. Rodionov ◽  
Yu. V. Khlebnikova ◽  
I. N. Stepanova ◽  
...  
Keyword(s):  
Room Temperature ◽  
Secondary Recrystallization ◽  
Cube Texture ◽  
Deformation Texture ◽  
Primary Recrystallization ◽  
Pure Nickel ◽  
Rolling Temperature ◽  
Different Temperatures ◽  
Kinetics Of ◽  
Thin Tape

The effect of the rolling temperature on the deformation texture and the perfection degree of a cube texture in pure-nickel thin tape were investigated. The kinetics of primary recrystallization was studied on samples that had undergone rolling at different temperatures and the temperature of the onset of secondary recrystallization was determined. Regularities of the structure formation in the samples are discussed. It is established that the cube texture with the maximum sharpness is produced in the samples rolled at room temperature.

scholarly journals Kinetics of solute leachate from imbibing Caesalpinia echinata Lam. (Brazilwood) seeds

Revista CERES ◽  
2014 ◽  
Vol 61 (1) ◽  
pp. 90-97 ◽  
Author(s):  
Nestor Martini Neto ◽  
Edmir Vicente Lamarca ◽  
Claudio José Barbedo
Keyword(s):  
Seed Coat ◽  
Room Temperature ◽  
Initial Moisture Content ◽  
Leaching Kinetics ◽  
Leaching Rate ◽  
Different Temperatures ◽  
Physiological Quality ◽  
Rapid Tests ◽  
Caesalpinia Echinata ◽  
Kinetics Of

The electrical conductivity of leachates from imbibing seeds has been used as a vigor test for several species. The adaptation of this methodology to different species requires knowledge on the leaching kinetics of electrolytes. For Brazilwood seeds, the classic method was not satisfactory and rapid tests are essential because they have low storage capacity at room temperature. Leaching kinetics during seed imbibition is a function of physiological quality, presence or absence of seed coat, imbibing temperature and the initial moisture content of seed. In this study, the electrolyte leaching rate of six different categories of seeds, from two regions, was evaluated in seeds with and without seed coat and incubated with different moisture contents and at different temperatures. The results showed that the electrolyte leaching rate in Brazilwood seeds is independent of the physiological quality, the presence or absence of seed coat and imbibition temperature, but these factors changed the total amount of electrolytes leached. The leaching rate increased in the first few minutes of imbibition, suggesting that the adjustment of the methodology must consider the reduction in imbibition time, reduction in temperature, use of a controlled and slower pre-imbibition, and replacement of the imbibition solution after the first few minutes.

scholarly journals SEED GERMINATION AND SEEDLING ESTABLISHMENT OF CHERIMOYA (ANNONA CHERIMOLA MILL.) AT DIFFERENT TEMPERATURES

2020 ◽  
Vol 53 (2) ◽  
pp. 185-194
Author(s):  
A. KHELOUFI ◽  
L. M. MANSOURI ◽  
H. KHETTACHE
Keyword(s):  
Seed Germination ◽  
Room Temperature ◽  
Germination Percentage ◽  
Annona Cherimola ◽  
Seedling Length ◽  
Different Temperatures ◽  
External Conditions ◽  
Mean Germination Time ◽  
Coefficient Of Velocity ◽  
Kinetics Of

Cherimoya (Annona cherimola Mill.) has an exceptional flavor and aroma, which makes it a fruit with great potential. However, little is known about its propagation by seeds. According to the scientific literature, the germination of cherimoya seeds is affected much more by external conditions than by internal conditions. Germination of cherimoya variety ‘Concha Lisa’ were tested for germination at constant temperatures of 25, 30, 40°C, and at room temperature, varying from 20-25°C, coupled with total darkness. Seeds were sown in Petri dishes (0.8% agar water), for 25 days of incubation. The kinetics of germination was determined according to five closely related parameters, viz. final germination percentage (FGP), mean germination time (MGT), coefficient of velocity of germination (CVG), time to 50% germination (T50) and seedling length (SL). The temperature of 30°C was found optimally suitable with 70.8% FGP, 17.5 days MGT and 3.91 cm SL, while the room temperature of 20-25°C slightly improved germination with only 25% FGP. Furthermore, significant decrease in FGP and SL was observed at 25°C and 40°C of temperature in comparison to 30°C. The analysis also revealed that cherimoya seed germination, day 10-15 after seed sowing is suitable for final counts. An overview on the emergence of cherimoya seedlings, during a 12-week period in pots is presented.

Kinetics of Cu Segregation in Al-Cu(1at% Cu) Interconnects Studied by Resistance Measurements

1997 ◽  
Vol 473 ◽  
Author(s):  
A. J. Kalkman ◽  
A. H. Verbruggen ◽  
G. C. A. M. Janssen ◽  
S. Radelaar
Keyword(s):  
Thin Films ◽  
Activation Energy ◽  
Grain Boundary ◽  
Room Temperature ◽  
Boundary Diffusion ◽  
Measurement Temperature ◽  
Temperature Range ◽  
Different Temperatures ◽  
Resistance Decrease ◽  
Kinetics Of

ABSTRACTThe time-dependence of the growth of Al2Cu precipitates in Al-Cu(lat% Cu) thin films is studied by means of resistance measurements at different temperatures. The samples are annealed at 400°C for 1 hour, and then quickly cooled down to room temperature. Afterwards, the samples are heated within one minute to a measurement temperature between 140 °C and 240 °C. Growth of precipitates causes a well defined decrease in resistance. The observed resistance decrease does not follow an exponential decay. In the investigated temperature range the resistance decrease can be accurately modelled by (R(t)-R∞) = (Ro-R∞)exp(-(t /τ)n), with the time constant τ= τ0 exp(Ea / kT). Excellent fits were obtained resulting in n = 0.66±0.05, independent of temperature, and Ea= 0.81±0.03 eV. This value for the activation energy agrees very well with the activation energy that has been reported in literature for both electromigration failure in Al-Cu and grain-boundary diffusion of Cu in Al. The value we found for n is intriguingly close to 2/3 and deviates strongly from the values of n reported for bulk Al-Cu (n = 1.5–1.8) in the same temperature range.

scholarly journals Facile Preparation of Granular Copper Films as Cathode for Enhanced Electrochemical Degradation of Methyl Orange

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2697
Author(s):  
Jiajie Xing ◽  
Min Song ◽  
Mengyao Yang ◽  
Xu Tan ◽  
Fenglin Li ◽  
...  
Keyword(s):  
Methyl Orange ◽  
Room Temperature ◽  
Ph Value ◽  
Copper Films ◽  
Electrochemical Degradation ◽  
Degradation Reaction ◽  
Facile Preparation ◽  
Neutral Conditions ◽  
Kinetics Of ◽  
Degradation Of Methyl Orange

In this paper, granular copper films (GCFs) were prepared through electrodeposition in CuSO4 solution containing triethanolamine, and the films were used as electro-Fenton-like cathodes for degradation of methyl orange (MO). The effects of triethanolamine concentration, pH value, current intensity and temperature on the morphology of the films, as well as the MO decolorization ratio (DR), were investigated in detail. Results show that when the concentration of triethanolamine is 0.2 wt%, the prepared GCF exhibits the best performance. Under room temperature and neutral conditions, no external O2 or catalyst, MO is completely decolorized after 240 min. Compared with the commonly used carbon cathode, the GCF cathode can increase the MO decolorization rate by approximately 70.9%. The kinetics of the electrochemical degradation reaction is also discussed.

scholarly journals Effect of the buffer system on stability of tetracaine hydrochloride 0.5% eyedrops

2001 ◽  
Vol 47 ◽  
pp. 15-20
Author(s):  
Emilija Fredro-Kumbaradzi ◽  
Tanja Milenkoska ◽  
Marija Glavas-Dodov ◽  
Katerina Goracinova ◽  
Kristina Mladenovska
Keyword(s):  
Degradation Rate ◽  
Ph Value ◽  
Degradation Products ◽  
Borate Buffer ◽  
Buffer System ◽  
Constant Ph ◽  
Accelerated Stability ◽  
Different Temperatures ◽  
The Stability

The effect of the buffer system on the stability of tetracaine hydrochloride in eyedrop formulation was evaluated. Eyedrop formulations containing tetracaine hydrochloride 0.5%(w/v) were prepared using different buffer systems (acetate, phosphate and borate buffer) under a constant pH of 5.4, and a buffer concentration of 0.06M. Long-term tests at 26 o C and accelerated stability tests at elevated temperature (45, 50, 60 o C) over a period of 168 days were carried out by following the macroscopic view, pH, sterility, content of tetracaine hydrochloride and detection of the degradation products. Also, values of the constant of degradation rate at different temperatures and t90% were calculated. The phosphate and acetate buffers provided satisfactory stability of tetracaine hydrochloride eyedrops, while borate buffer was not sufficient to maintain the pH value of the solution.

Kinetic Study on Crude Laccase of Marasmius sp. from Solid State Fermentation

2020 ◽  
Vol 840 ◽  
pp. 131-136
Author(s):  
Hendro Risdianto ◽  
Susi Sugesty
Keyword(s):  
Solid State ◽  
Kinetic Study ◽  
Solid State Fermentation ◽  
Sulfonic Acid ◽  
Room Temperature ◽  
Maximum Activity ◽  
Cold Temperatures ◽  
Fermentation Method ◽  
Optimum Ph ◽  
Kinetics Of

Crude laccase was produced by using the fermentation method of solid state fermentation and employed fungus Marasmius sp and rice straw as support media. The kinetics of laccase was investigated by using the substrate of 2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). Laccase exhibits the maximum activity (Vm) of 1.45 mM/min and Michaelis-Menten (Km) constant value of 4.11 mM. The effect of pH and temperature has also been evaluated. The results showed that this enzyme had an optimum pH of 4.6 and temperature of 60 °C. Decreased stability of laccases is found to be faster when stored at room temperature than cold temperatures.

scholarly journals Akinetic study of the depyritization of oil shale HCl-kerogen concentrate by Thiobacillus ferrooxidans at different temperatures

2003 ◽  
Vol 68 (4-5) ◽  
pp. 417-423 ◽  
Author(s):  
Miroslav Vrvic ◽  
Vesna Dragutinovic ◽  
Valerija Matic ◽  
Snezana Spasic ◽  
Olga Cvetkovic ◽  
...  
Keyword(s):  
Oil Shale ◽  
Thiobacillus Ferrooxidans ◽  
Ph Value ◽  
Kinetic Studies ◽  
Low Ph ◽  
Process Efficiency ◽  
Cell Interior ◽  
Biochemical Kinetics ◽  
Different Temperatures ◽  
Kinetics Of

The results of kinetic studies of bacterial depyritization of HCl-kerogen concentrate of Aleksinac (Serbia) oil shale by the chemolithoautotrophic thionic bacteria Thiobacillus ferrooxidans under discontinuous laboratory conditions at various temperatures (0, 20, 28 and 37 ?C) at a pH of ca. 1.5 are presented in this paper. Low pH prevents the occurrence of the precipitation of iron(III)-ion hydrolysis products on the substrate particles and thereby reduces the process efficiency. Bacterial depyritization is developed as per kinetics of the first order. The activation energy which points to a successive mechanism of pyrite biooxidation, was computed from the Arrhenius plot. The biochemical kinetics indicators point to a high affinity of the bacteria toward pyrite but small values of Vmax, which are probably the result of decelerated metabolic processes due to the low pH value of the environment resp. the large difference of thepHbetween the external medium and the cell interior.

Investigation of irradiation-induced nucleation processes in silicon and germanium

1995 ◽  
Vol 53 ◽  
pp. 224-225
Author(s):  
Harry A. Atwater ◽  
C.M. Yang ◽  
K.V. Shcheglov
Keyword(s):  
Room Temperature ◽  
Crystal Size ◽  
Initial Distribution ◽  
Engineering Control ◽  
Size Evolution ◽  
Silicon And Germanium ◽  
Ge Quantum Dot ◽  
And Control ◽  
Germanium Quantum Dots ◽  
Kinetics Of

Studies of the initial stages of nucleation of silicon and germanium have yielded insights that point the way to achievement of engineering control over crystal size evolution at the nanometer scale. In addition to their importance in understanding fundamental issues in nucleation, these studies are relevant to efforts to (i) control the size distributions of silicon and germanium “quantum dots𠇍, which will in turn enable control of the optical properties of these materials, (ii) and control the kinetics of crystallization of amorphous silicon and germanium films on amorphous insulating substrates so as to, e.g., produce crystalline grains of essentially arbitrary size.Ge quantum dot nanocrystals with average sizes between 2 nm and 9 nm were formed by room temperature ion implantation into SiO2, followed by precipitation during thermal anneals at temperatures between 30°C and 1200°C[1]. Surprisingly, it was found that Ge nanocrystal nucleation occurs at room temperature as shown in Fig. 1, and that subsequent microstructural evolution occurred via coarsening of the initial distribution.

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