Kinetic Study, by UV–Vis Spectroscopy, on the Strong Effect of LiCl on the Controlled Polymerization of 2-Bromo-3-hexyl-5-iodothiophene and 2-Iodo-3-hexyl-5-bromothiophene: Determination of the Propagation Rate Constants, Application to the Synthesis of High Molecular Weight Polydodecylthiophene

2011 ◽  
Vol 44 (20) ◽  
pp. 7962-7968 ◽  
Author(s):  
J.-P. Lamps ◽  
J.-M. Catala
Keyword(s):  
Molecular Weight ◽  
Kinetic Study ◽  
High Molecular Weight ◽  
Rate Constants ◽  
Propagation Rate ◽  
Controlled Polymerization ◽  
Vis Spectroscopy

scholarly journals Effects of Delayed Sample Processing on Determination of Total and High Molecular Weight (HMW) Adiponectin in Serum and Plasma: A Pilot Study

2016 ◽  
Vol 8 (3) ◽  
pp. 19
Author(s):  
Choaping Ng ◽  
Felicity J Rose ◽  
Sahar Keshvari ◽  
Marina M Reeves ◽  
Goce Dimeski ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Pilot Study ◽  
High Molecular Weight ◽  
Accurate Determination ◽  
Mean Difference ◽  
Serum Samples ◽  
Blood Samples ◽  
Hmw Adiponectin ◽  
Total Adiponectin

<p>Adiponectin is a beneficial adipocyte-secreted hormone, which circulates in a variety of multimeric forms termed low and high molecular weight (LMW/HMW). Effectiveness of clinical therapeutic trials which target adiponectin rely on accurate determination of circulating total and HMW adiponectin levels but the accuracy may be influenced by variations in sample handling processes. The aim of this pilot study was to investigate the effects of delayed processing of blood samples on the concentration of total and HMW adiponectin.</p><p>Materials and Methods: Fasting blood samples were collected for analysis of total and HMW adiponectin concentrations in EDTA plasma and serum from eight healthy participants.  Samples were centrifuged post 15 min storage at 4<sup>o</sup>C as the comparative ‘ideal’ method or after up to 72 h of refrigerated storage or 6 h at room temperature. Total and HMW adiponectin concentrations were measured by ELISA.</p><p>Results: Under ideal handling conditions measurements of total and HMW adiponectin concentrations were significantly higher in serum than in plasma (mean difference: -1.3 µg/mL [95% CI: -1.6, -1.0], p&lt;0.001; and, -0.6 µg/mL [95% CI: -0.7, -0.5], p&lt;0.001, respectively).  Storage of blood samples at 4<sup>o</sup>C for 72 h resulted in significant reductions in concentration of total adiponectin in serum (mean difference: -1.4 µg/mL [95% CI: -2.0, -0.8], p=0.001) and HMW adiponectin in plasma (mean difference: -0.6 µg/mL [95%CI: -0.9, -0.2], p=0.007), compared with ideal conditions.  Further analysis of serum samples showed a significant decrease in total adiponectin concentration after 6 h storage at 4<sup>o</sup>C (mean difference: -1.4 µg/mL [95% CI: -2.0, -0.8], p=0.001) compared with ideal conditions.</p><p>Conclusions: Delayed processing of samples may have differential effects on the concentration of total and HMW adiponectin in serum or plasma. Larger studies are warranted for clinical intervention trials.</p>

scholarly journals Determination of dielectric properties of a high-molecular weight DNA

Biopolymers ◽  
1978 ◽  
Vol 17 (9) ◽  
pp. 2279-2283 ◽  
Author(s):  
A. Surowiec
Keyword(s):  
Molecular Weight ◽  
Dielectric Properties ◽  
High Molecular Weight ◽  
High Molecular Weight Dna

Flame Response in the Quantitative Determination of High Molecular Weight Paraffins and Alcohols by Gas Chromatography.

1963 ◽  
Vol 35 (3) ◽  
pp. 360-362 ◽  
Author(s):  
Gerald. Perkins ◽  
R. E. Laramy ◽  
L. D. Lively
Keyword(s):  
Molecular Weight ◽  
Gas Chromatography ◽  
Quantitative Determination ◽  
High Molecular Weight ◽  
Flame Response

Determination of Peroxides in Synthetic Rubbers

1945 ◽  
Vol 18 (4) ◽  
pp. 874-876
Author(s):  
Richard F. Robey ◽  
Herbert K. Wiese
Keyword(s):  
Molecular Weight ◽  
Natural Rubber ◽  
Quantitative Determination ◽  
High Molecular Weight ◽  
Active Oxygen ◽  
Lower Molecular Weight ◽  
Synthetic Rubber ◽  
High Molecular Weight Polymers ◽  
Methanol Solutions

Abstract Peroxides are found in synthetic rubbers either as the result of attack by oxygen, usually from the air, or as a residue from polymerization operations employing peroxide catalysts. Because of possible detrimental effects of active oxygen on the properties of the rubber, a method of quantitative determination is needed. The concentration of peroxides in substances of lower molecular weight may be determined with ferrous thiocyanate reagent, either titrimetrically as recommended by Yule and Wilson or colorimetrically as by Young, Vogt, and Nieuwland. Unfortunately, many highly polymeric substances are not soluble in the acetone and methanol solutions employed in these procedures. This is also the case with hydrocarbon monomers, such as butadiene, containing appreciable concentrations of soluble high molecular weight polymers. Bolland, Sundralingam, Sutton and Tristram recommended benzene as a solvent for natural rubber samples and the reagent made up in methanol. However, most synthetic rubbers are not readily soluble even in this combination. The following procedure employs the ferrous thiocyanate reagent in combination with a solvent capable of maintaining considerable concentrations of synthetic rubber in solution. The solvent comprises essentially 20 per cent ethanol in chloroform.

Determination of propagation rate constants for the copolymerization of methymethacrylate and styrene using a pulsed laser technique

1989 ◽  
Vol 27 (6) ◽  
pp. 181-185 ◽  
Author(s):  
Thomas P. Davis ◽  
Kenneth F. O'Driscoll ◽  
Mark C. Piton ◽  
Mitchell A. Winnik
Keyword(s):  
Rate Constants ◽  
Pulsed Laser ◽  
Propagation Rate ◽  
Laser Technique

scholarly journals Quantitative Determination of Low and High Molecular Weight Proteins in Human Urine: Influence of Temperature and Storage Time

1999 ◽  
Vol 45 (3) ◽  
pp. 430-432 ◽  
Author(s):  
Ina S Klasen ◽  
Louis JM Reichert ◽  
Corrie M de Kat Angelino ◽  
Jack FM Wetzels
Keyword(s):  
Molecular Weight ◽  
Quantitative Determination ◽  
High Molecular Weight ◽  
Human Urine ◽  
Storage Time ◽  
Influence Of Temperature ◽  
High Molecular Weight Proteins ◽  
And Storage

Gas chromatographic mass spectrometric determination of high-molecular-weight polycyclic aromatic hydrocarbons in coal tar

1983 ◽  
Vol 55 (7) ◽  
pp. 1030-1033 ◽  
Author(s):  
Thomas. Romanowski ◽  
Werner. Funcke ◽  
Irmhild. Grossmann ◽  
Johann. Koenig ◽  
Eckhard. Balfanz
Keyword(s):  
Molecular Weight ◽  
Polycyclic Aromatic Hydrocarbons ◽  
High Molecular Weight ◽  
Aromatic Hydrocarbons ◽  
Coal Tar ◽  
Mass Spectrometric ◽  
Mass Spectrometric Determination ◽  
Polycyclic Aromatic ◽  
Chromatographic Mass
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