HEATS OF MIXING OF POLYISOBUTYLENE WITH SOME ORGANIC SOLVENTS

1960 ◽  
Vol 38 (7) ◽  
pp. 1087-1091 ◽  
Author(s):  
Claude Watters ◽  
Hubert Daoust ◽  
Marcel Rinfret
Keyword(s):  
Molecular Weight ◽  
Organic Solvents ◽  
Polymer Solutions ◽  
High Polymer ◽  
Molecular Weight Range ◽  
Polymer Sample ◽  
Weight Range ◽  
Calvet Microcalorimeter ◽  
Heats Of Mixing ◽  
Scatchard Equation

The heats of mixing of four fractions of polyisobutylene with five organic solvents have been measured at 25 °C with the use of a Tian–Calvet microcalorimeter. The maximum concentrations attained were of the order of 3% in polymer. It has been found that the enthalpy parameter k0 is independent of the molecular weight of the polymer sample in the investigated molecular weight range. All the values for k0 calculated from the Van Laar–Scatchard equation for the different polymer–solvent pairs are different from the values estimated from the partial molal quantities. This is explained with the use of new theories on the thermodynamics of high polymer solutions by Orofino and Flory and by Huggins.

scholarly journals Nuclear matrix of HeLa S3 cells. Polypeptide composition during adenovirus infection and in phases of the cell cycle.

1977 ◽  
Vol 72 (1) ◽  
pp. 194-208 ◽  
Author(s):  
L D Hodge ◽  
P Mancini ◽  
F M Davis ◽  
P Heywood
Keyword(s):  
Cell Cycle ◽  
Molecular Weight ◽  
Nuclear Matrix ◽  
Apparent Molecular Weight ◽  
Molecular Weight Range ◽  
Weight Range ◽  
Molecular Weights ◽  
Liver Nuclei ◽  
Hela S3 ◽  
Biochemical Analyses

A subnuclear fraction has been isolated from HeLa S3 nuclei after treatment with high salt buffer, deoxyribonuclease, and dithiothreitol. This fraction retains the approximate size and shape of nuclei and resembles the nuclear matrix recently isolated from rat liver nuclei. Ultrastructural and biochemical analyses indicate that this structure consists of nonmembranous elements as well as some membranous elements. Its chemical composition is 87% protein, 12% phospholipid, 1% DNA, and 0.1% RNA by weight. The protein constituents are resolved in SDS-polyacrylamide slab gels into 30-35 distinguishable bands in the apparent molecular weight range of 14,000 - 200,000 with major peptides at 14,000 - 18,000 and 45,000 - 75,000. Analysis of newly synthesized polypeptides by cylindrical gel electrophoresis reveals another cluster in the 90,000-130,000 molecular weight range. Infection with adenovirus results in an altered polypeptide profile. Additional polypeptides with apparent molecular weights of 21,000, 23,000, and 92,000 become major components by 22 h after infection. Concomitantly, some peptides in the 45,000-75,000 mol wt range become less prominent. In synchronized cells the relative staining capacity of the six bands in the 45,000-75,000 mol wt range changes during the cell cycle. Synthesis of at least some matrix polypeptides occures in all phases of the cell cycle, although there is decreased synthesis in late S/G2. In the absence of protein synthesis after cell division, at least some polypeptides in the 45,000-75,000 mol wt range survive nuclear dispersal and subsequent reformation during mitosis. The possible significance of this subnuclear structure with regard to structure-function relationships within the nucleus during virus replication and during the life cycle of the cell is discussed.

Uremic Neurotoxin in the Middle Molecular Weight Range

1980 ◽  
Vol 4 (2) ◽  
pp. 116-120 ◽  
Author(s):  
N.K. Man ◽  
G. Cueille ◽  
J. Zingraff ◽  
J. Boudet ◽  
A. Sausse ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Range ◽  
Weight Range

Aqueous polypropylene glycol induces swelling and severe plasticization of high Tg amphiphilic copolymers containing hexafluoroisopropanol groups

Soft Matter ◽  
2020 ◽  
Vol 16 (27) ◽  
pp. 6362-6370
Author(s):  
Siyuan Li ◽  
Bryan D. Vogt
Keyword(s):  
Molecular Weight ◽  
Propylene Glycol ◽  
Polypropylene Glycol ◽  
Amphiphilic Copolymers ◽  
Molecular Weight Range ◽  
Weight Range ◽  
Poly Propylene

Not too big, not too small, but a narrow molecular weight range for poly(propylene glycol) where swelling of the copolymer increases tremendously for poly(propylene glycol).

Forces between poly-l-lysine of molecular weight range 4,000–75,000 adsorbed on mica surfaces

1987 ◽  
Vol 25 (2-4) ◽  
pp. 263-277 ◽  
Author(s):  
T. Afshar-rad ◽  
A.I. Bailey ◽  
P.F. Luckham ◽  
W. Macnaughtan ◽  
D. Chapman
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Range ◽  
Weight Range

IMMUNOREACTIVE β-MSH IN HUMAN PLASMA AND IN A CORTICOTROPHIC ADENOMA CULTURE MEDIUM. ITS RELATION TO THE LIPOTROPHINS

1979 ◽  
Vol 90 (1) ◽  
pp. 8-17
Author(s):  
X. Bertagna ◽  
M. Donnadieu ◽  
D. Seurin ◽  
M. Binoux ◽  
F. Girard
Keyword(s):  
Molecular Weight ◽  
Culture Medium ◽  
Addison’S Disease ◽  
Main Peak ◽  
Addison's Disease ◽  
Ph Change ◽  
Nelson’S Syndrome ◽  
Molecular Weight Range ◽  
Weight Range ◽  
Nelson's Syndrome

ABSTRACT In order to characterize more accurately the relationship between immunoreactive β-MSH ("β-MSH") and the lipotrophins (LPH) we attempted to investigate the gel filtration and the immunological characteristics of "β-MSH" in the plasma of patients with Nelson's syndrome and Addison's disease as well as in the culture medium from a human corticotrophic adenoma using a sensitive radioimmunoassay from human β-MSH. When added either to hormone free plasma or to a plasma from a patient with Nelson's syndrome all the human β-MSH (hβ-MSH) elutes from a Sephadex G-50 column as a single peak in a volume corresponding to its molecular weight. In contrast plasma "β-MSH" in 3 patients with Nelson's syndrome and one patient with Addison's disease almost completely elutes in a volume corresponding to a molecular weight range of 6000– 10 000; no "β-MSH" can be detected in its normal elution volume. Drastic pH change (8.2 to 2.3) does not significantly alter the elution pattern. Chromatography of a corticotrophic adenoma culture medium gave a similar pattern of "β-MSH" with a main peak in the molecular weight range of 6000–10 000. In our radioimmunoassay the culture medium and purified hβ-LPH gave parallel displacement curves for [125I]hβ-MSH. It is suggested that hβ-LPH or a closely related substance is the main material responsible for "β-MSH" immunoactivity.

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