Use of a colorimetric method of peroxide analysis for determining the rate constant for homolytic rupture of the peroxide bond in dicyclohexylperoxydicarbonate

1980 ◽  
Vol 29 (4) ◽  
pp. 543-547
Author(s):  
Z. S. Kartasheva ◽  
A. B. Gargarina
Keyword(s):  
Rate Constant ◽  
Colorimetric Method ◽  
Peroxide Bond

Functional Properties of p-Anisoylated Plasmin-Staphylokinase Complex

1993 ◽  
Vol 70 (02) ◽  
pp. 326-331 ◽  
Author(s):  
H R Lijnen ◽  
B Van Hoef ◽  
R A G Smith ◽  
D Collen
Keyword(s):  
Human Plasma ◽  
Rate Constant ◽  
Time Course ◽  
Bolus Injection ◽  
Similar Rate ◽  
Clot Lysis ◽  
Lag Phase ◽  
Plasma Clot ◽  
Rapid Clearance ◽  
Stoichiometric Complex

SummaryThe kinetic and fibrinolytic properties of a reversibly acylated stoichiometric complex between human plasmin and recombinant staphylokinase (plasmin-STAR complex) were evaluated. The acylation rate constant of plasmin-STAR by p-amidinophenyl-p’-anisate-HCI was 52 M-1 s-1 and its deacylation rate constant 1.2 × 10-4 s-1 (t½ of 95 min) which are respectively 50-fold and around 3-fold lower than for the plasmin-streptokinase complex. The acylated complex was stable as evidenced by binding to lysine-Sepharose. However, following an initial short lag phase, the acylated plasmin-STAR complex activated plasminogen at a similar rate as the unblocked complex, whereas the acylated plasmin-streptokinase complex did not activate plasminogen. These findings indicate that STAR, unlike streptokinase, dissociates from its acylated complex with plasmin in the presence of excess plasminogen. In agreement with this hypothesis, the time course of the lysis of a 125I-fibrin labeled plasma clot submerged in citrated human plasma, is similar for acylated plasmin-STAR, unblocked plasmin-STAR and free STAR (50% clot lysis in 2 h requires 12 nM of each agent). The plasma clearances of STAR-related antigen following bolus injection in hamsters were 1.0 to 1.5 ml/min for acylated plasmin-STAR, unblocked plasmin-STAR and free STAR, as a result of short initial half-lives of 2.0 to 2.5 min.The dissociation of the anisoylated plasmin-STAR complex and its consequent rapid clearance suggest that it has no apparent advantages as compared to free STAR for clinical thrombolysis.

Morphological and Photodecomposition Rate Constant Study of PVC Films Doped with Sulfadiazine Tin(IV) Complexes

2020 ◽  
Vol 14 (2) ◽  
pp. 88
Author(s):  
Emad Yousif
Keyword(s):  
Radiation Exposure ◽  
Uv Radiation ◽  
Rate Constant ◽  
Experimental Results

This article focus on the calculation of photodecomposition rate constant of PVC films that containing sulfadiazine tin(IV) complexes 1-3 as photostabilzers during UV radiation exposure. This constant calculated as a method for evaluating the efficiency of sulfadiazine tin(IV) complexes 1-3 when used as a PVC photostabilizers after 300 hours of irradiation. The experimental results showed that sulfadiazine tin(IV) complexes 1-3 have reduced the rate of photodecomposition constant value of PVC films significantly with comparison to PVC (blank).

Dynamic Emergence of Nanostructure and Transport Properties in Perfluorinated Sulfonic Acid Ionomers

2020 ◽  
Author(s):  
Adlai Katzenberg ◽  
Debdyuti Mukherjee ◽  
Peter J. Dudenas ◽  
Yoshiyuki Okamoto ◽  
Ahmet Kusoglu ◽  
...  
Keyword(s):  
Rate Constant ◽  
Sulfonic Acid ◽  
Mass Fraction ◽  
Gas Permeability ◽  
Transport Processes ◽  
Segmental Mobility ◽  
The Matrix ◽  
Swelling Rate ◽  
Ion Conducting ◽  
Perfluorinated Sulfonic Acid

<p>Limitations in fuel cell electrode performance have motivated the development of ion-conducting binders (ionomers) with high gas permeability. Such ionomers have been achieved by copolymerization of perfluorinated sulfonic acid (PFSA) monomers with bulky and asymmetric monomers, leading to a glassy ionomer matrix with chemical and mechanical properties that differ substantially from common PFSA ionomers (e.g., Nafion™). In this study, we use perfluorodioxolane-based ionomers to provide fundamental insights into the role of the matrix chemical structure on the dynamics of structural and transport processes in ion-conducting polymers. Through <i>in-situ</i> water uptake measurements, we demonstrate that ionomer water sorption kinetics depend strongly on the properties and mass fraction of the matrix. As the PFSA mass fraction was increased from 0.26 to 0.57, the Fickian swelling rate constant decreased from 0.8 s<sup>-1</sup> to 0.2 s<sup>-1</sup>, while the relaxation rate constant increased from 3.1×10<sup>-3</sup> s<sup>-1</sup> to 4.0×10<sup>-3</sup>. The true swelling rate, in nm s<sup>-1</sup>, was determined by the chemical nature of the matrix; all dioxolane-containing materials exhibited swelling rates ~1.5 - 2 nm s<sup>-1</sup> compared to ~3 nm s<sup>-1</sup> for Nafion. Likewise, Nafion underwent relaxation at twice the rate of the fastest-relaxing dioxolane ionomer. Reduced swelling and relaxation kinetics are due to limited matrix segmental mobility of the dioxolane-containing ionomers. We demonstrate that changes in conductivity are strongly tied to the polymer relaxation, revealing the decoupled roles of initial swelling and relaxation on hydration, nanostructure, and ion transport in perfluorinated ionomers. </p>

Development of Sustained Release Multi-Component Microparticulate System of Diclofenac Sodium and Tizanidine Hydrochloride

1970 ◽  
Vol 1 (1) ◽  
pp. 97-105
Author(s):  
Kamlesh Dashora ◽  
Shailendra Saraf ◽  
Swarnalata Saraf
Keyword(s):  
Particle Size ◽  
Sustained Release ◽  
Cellulose Acetate ◽  
Rate Constant ◽  
Diclofenac Sodium ◽  
Order Rate Constant ◽  
Anomalous Transport ◽  
First Order ◽  
Sem Study ◽  
Transport Type

Sustained released tablets of diclofenac sodium (DIC) and tizanidine hydrochloride (TIZ) were prepared by using different proportions of cellulose acetate (CA) as the retardant material. Nine formulations of tablets having different proportion of microparticles developed by varied proportions of polymer: drug ratio ‘’i.e.’’; 1:9 -1:3 for DIC and 1:1 – 3:1 for TIZ. Each tablet contained equivalent to 100 mg of DIC and 6mg of TIZ. The prepared microparticles were white, free flowing and spherical in shape (SEM study), with  the particle size varying from 78.8±1.94 to 103.33±1.28 µm and 175.92± 9.82 to 194.94±14.28µm for DIC  and TIZ, respectively.  The first order rate constant K1 of formulations were found to be in the range of  K1 = 0.117-0.272 and 0.083- 0.189 %hr-1for DIC and TIZ, respectively. The value of exponent coefficient (n) was found to be in the range of 0.6328-0.9412  and 0.8589-1.1954 for DIC and TIZ respectively indicates anomalous  to  non anomalous transport type of diffusions among different formulations

The Reference Intervals Used in Pediatric Medical Analysis Laboratories to Interpret the Results Analysis for Total Serum Calcium

2017 ◽  
Vol 68 (2) ◽  
pp. 243-245
Author(s):  
Elisabeta Antonescu ◽  
Maria Totan ◽  
Gheorghe Cornel Boitor ◽  
Julianna Szakacs ◽  
Sinziana Calina Silisteanu ◽  
...  
Keyword(s):  
Serum Calcium ◽  
Colorimetric Method ◽  
Age Groups ◽  
Essential Element ◽  
Reference Intervals ◽  
Total Serum ◽  
Electronic Archive ◽  
Total Serum Calcium ◽  
Analysis Laboratory ◽  
Medical Analysis

Medical analysis laboratory must establish its own reference intervals depending on the facilities they are working with, the working substances and protocols. These reference intervals must be obtained depending on age groups in order to accurately interpret the results of the analyzes performed. The study is a retrospective one using 3217 data from the electronic archive of the S.C. Vladutiu&Garabedian S.R.L. Clinic in Medias. Total serum calcium was determined by the colorimetric method on the Konelab analyzer. Processing of the collected data was done using the Hoffmann method, considering 5% up to 95% of the values in the database, the values being randomly selected. For comparison, data from the literature was used. In children under 1 year old, it was not possible to calculate the reference intervals since data was insufficient. In the other age groups, reference intervals obtained in the current study were similar to the studied literature. Reference intervals established for calcium can provide important guidance for the reasonable supplementation of this essential element in children.

Sedimentation of Pb-210 in Laurentian Shield Lakes

1984 ◽  
Vol 19 (2) ◽  
pp. 97-109 ◽  
Author(s):  
R.J. Cornett ◽  
L. Chant ◽  
D. Link
Keyword(s):  
Lake Sediments ◽  
Water Column ◽  
Rate Constant ◽  
Bottom Sediments ◽  
Atmospheric Fallout ◽  
Small Lakes ◽  
Fractional Rate ◽  
Total Input ◽  
Shield Lakes ◽  
Annual Flux

Abstract The average annual flux of Pb-210 from the atmosphere to lake surfaces and to the bottom sediments was measured in seven small lakes located on the Laurentian Shield. Direct atmospheric fallout of Pb-210 was 136 ± 16 Bq m-2 a-1 Streams from the lakes' catchments input an additional 5 to 473 Bq m-2 a-1. Only 16 to 80 percent of the total input was found in the lake sediments. The fractional rate constant for Pb-210 sedimentation from the water column ranged from 0.25 to 5.3 per annum.

Creatinuria and Dynamics of Calcium Metabolism in Children in the Phase of Exacerbation of Bronchial Asthma

2020 ◽  
Vol 16 (1) ◽  
pp. 28-33
Author(s):  
Vitalii B. Kaliberdenko ◽  
Shanmugaraj Kulanthaivel ◽  
Michael V. Shterenshis ◽  
Olga Y. Poleshchuk ◽  
Kadri Mametov ◽  
...  
Keyword(s):  
Creatine Kinase ◽  
Blood Serum ◽  
Bronchial Asthma ◽  
Picric Acid ◽  
Colorimetric Method ◽  
Cellular Level ◽  
Creatine Kinase Activity ◽  
Biological Medium ◽  
Creatinine Concentration ◽  
Test Kit

: Bronchial asthma is one of the most common and severe diseases among children. The phenomenon of creatinuria (CU) in patients with bronchial asthma (BA) has been acknowledged for a relatively long time. Aims: The Aim of the research is to study the level of creatinuria, creatinemia, creatine kinase activity, and the concentration of calcium in biological medium (blood, saliva, urine) in children suffering from an intermittent and persistent form of asthma during the period of exacerbation. Material and methods:: The research consists of 102 children with asthma who were treated in inpatient department in Simferopol Clinic. The intermittent course of asthma was recorded in 49 children and a persistent course of asthma was recorded in 53 children. The subject of study was blood serum and daily urine of observed patients. The level of calcium in the biological medium was studied using the "Filisit" test kit (Dnipro) and the activity of the creatine kinase by test set "Lahma". The levels of creatine and creatinine were determined using a colorimetric method based on a color reaction with picric acid. Results and conclusion: : The analysis testifies that creatinuria in children with persistent BA is caused by the disorder of the phosphorylation process rather than the disorder of creatinin rephosphorylation synthesis, that is testified by the normal creatinine level. In children with persistent BA, there is а decrease of creatinine concentration in the blood serum and urine during the exacerbation period and early post exacerbation period. The low activity of creatinine kinase at the background of creatinine elimination is typical for the children in the phase of exacerbation of persistent form of BA, though its level remains to be sufficient for the synthesis of the necessary amount of creatinine phosphate. Conclusion: The processes of creatinuria and calciuria in children suffering from a persistent form of BA are interdependent, that is testified by the data of correlative analysis. In connection with this, it is possible to consider the change of calcium homeostasis in the pathogenesis of the disease as one of the causes of distributing the creatinine metabolism on the cellular level.

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