Relative Influences of Riverine and Macroalgal Phenolic Materials on UV Absorbance in Temperate Coastal Waters

1983 ◽  
Vol 40 (8) ◽  
pp. 1258-1263 ◽  
Author(s):  
David J. Carlson ◽  
Lawrence M. Mayer
Keyword(s):  
Molecular Weight ◽  
Water Temperature ◽  
High Molecular Weight ◽  
Coastal Waters ◽  
Seasonal Changes ◽  
Gulf Of Maine ◽  
Uv Absorbance ◽  
Estuarine Mixing ◽  
Molecular Weight Fractions

Seasonal changes in profiles of both UV absorbance and phenolic material versus salinity were observed in some estuarine and coastal waters of the Gulf of Maine. Profiles of riverine UV-absorbent and phenolic materials were seasonally invariant, with slight losses from high molecular weight fractions during estuarine mixing. In estuaries containing significant populations of fucoid macroalgae, exudation by the macroalgae increased levels of these parameters by as much as threefold. These increases showed a strong seasonal pulsing, following water temperature. This pulsing was detectable in seasonal transects of adjacent shelf waters.

Some Osmotic Measurements of the Molecular Weight of a High Molecular-Weight Fraction of Rubber Hydrocarbon

1955 ◽  
Vol 28 (2) ◽  
pp. 504-507
Author(s):  
G. W. Drake
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Average Molecular Weight ◽  
Weight Fraction ◽  
Considerable Proportion ◽  
Prolonged Storage ◽  
High Molecular Weight Fraction ◽  
The United Kingdom ◽  
Molecular Weight Fractions ◽  
Temperate Climates

Abstract Fractionation of the rubber hydrocarbon in temperate climates has usually resulted in high molecular-weight fractions, with a molecular weight of the order of one million. Bloomfield has shown that fresh latex contains a considerable proportion of hydrocarbon having an intrinsic viscosity (η) of 10 or over and, therefore, a molecular weight of well over 106. The fractionation technique used by Bloomfield in Malaya has now been applied by the writer to smoked sheet and to F rubber, working in the United Kingdom. No very high molecular-weight fractions were found in the smoked sheet, but the F rubber yielded a fraction of (η)=7.3 and a number average molecular weight 6×106, determined osmometrically. The average molecular weight of natural rubber when freshly prepared is probably well over a million, and includes a substantial portion having a molecular weight of several millions. By the time smoked sheet has reached temperate climates, the high molecular-weight portion has probably been converted to gel. F rubber, presumably because of its different method of preparation, retains the major part of its high molecular-weight material during prolonged storage.

Uptake of Zinc by the Aquatic Larvae of Simulium ornatipes (Diptera : Nematocera)

1978 ◽  
Vol 29 (3) ◽  
pp. 299 ◽  
Author(s):  
JGT Carter ◽  
WL Nicholas
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Free Water ◽  
Weight Fraction ◽  
The Body ◽  
Ion Concentration ◽  
High Molecular Weight Fraction ◽  
Phosphonic Acids ◽  
Calcium Ion Concentration ◽  
Molecular Weight Fractions

The uptake and loss of zinc by the aquatic larvae of the blackfly S. ornatipes was investigated using radioactive 65Zn. Larvae may absorb significant quantities of zinc from solution, and a substantial proportion remains in the body when larvae are transferred to zinc-free water. Uptake is assisted by metabolism, but an increase of the calcium ion concentration, although reducing toxicity, has no effect on uptake, exchange or the loss of zinc. Larvae may be fractionated into 'cuticle', 'high-' and 'low-molecular-weight' fractions, based on solubility in water and 80% (v/v) ethanol. In the cuticle and high-molecular-weight fractions two 'pools' may be identified by dialysis against Na3EDTA -a pool in which zinc is weakly held and exchanges rapidly with the zinc in solution, and one where zinc is held and exchanges slowly. Exposure time, temperature, and external concentration influence the quantity of zinc entering these pools. Washing the cuticle and high-molecular-weight fractions with a series of buffers suggests that zinc is bound by phenolic groups in the cuticle fraction, and by phosphonic acids in the high-molecular-weight fraction. Sulfhydryl groups did not bind a major portion of the zinc.

Extraction, composition and the antioxidant and anticomplement activities of high molecular weight fractions from the leaves of Symphytum asperum and S. caucasicum

2011 ◽  
Vol 44 (11) ◽  
pp. 604-607 ◽  
Author(s):  
V. V. Barbakadze ◽  
K. G. Mulkidzhanyan ◽  
M. I. Merlani ◽  
L. M. Gogilashvili ◽  
L. Sh. Amiranashvili ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Molecular Weight Fractions

The Inhibition by Plasma of Urokinase and Tissue Activator-Induced Fibrinolysis in Pregnancy and the Puerperium

1983 ◽  
Vol 49 (01) ◽  
pp. 021-023 ◽  
Author(s):  
J E Walker ◽  
L Gow ◽  
D M Campbell ◽  
D Ogston
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Inhibitory Activity ◽  
Lower Molecular Weight ◽  
Amidolytic Activity ◽  
Third Trimester ◽  
The Third ◽  
Molecular Weight Fractions ◽  
In Pregnancy

SummaryThe activity of urokinase and tissue activator on fibrin plates was inhibited by plasma from women in the third trimester of pregnancy to a greater extent than by non-pregnant plasma. Pregnancy also inhibited the amidolytic activity of urokinase. The high molecular weight fractions of pregnancy plasma gel filtered on Sephadex G-200 showed comparable inhibitory activity against urokinase as fractions for non-pregnant plasma; in contrast with non-pregnant plasma, the lower molecular weight fractions of pregnancy plasma were markedly inhibitory against urokinase. Plasma exposed to lysine-Sepharose to remove plasminogen and then fractionated on Sephadex G-100 provided a pattern of three areas of inhibition against tissue activator similar to that seen in non-pregnant plasma. The urokinase-inhibitory activity of lower molecular weight fractions of plasma separated on Sephadex G-200 fell within 1 hr of delivery and fell further over the following 18 to 30 hr.

Association of c-myc protein with enzymes of DNA replication in high molecular weight fractions from mammalian cells

1991 ◽  
Vol 147 (3) ◽  
pp. 412-419 ◽  
Author(s):  
George P. Studzinski ◽  
Uma T. Shankavaram ◽  
Dorothy C. Moore ◽  
Prem Veer Reddy
Keyword(s):  
Molecular Weight ◽  
Dna Replication ◽  
High Molecular Weight ◽  
Mammalian Cells ◽  
Molecular Weight Fractions

Activation of monoamine oxidase by high molecular weight fractions of human plasma

1984 ◽  
Vol 120 (3) ◽  
pp. 337-341 ◽  
Author(s):  
LARS-OLOF WAHLUND ◽  
JAN SÄÄF ◽  
SVANTE B. ROSS ◽  
LENNART WETTERBERG
Keyword(s):  
Molecular Weight ◽  
Monoamine Oxidase ◽  
Human Plasma ◽  
High Molecular Weight ◽  
Molecular Weight Fractions

Mechanical Properties of Mammalian and Fish Gelatins as a Function of the Contents of α-Chain, β-Chain, and Low and High Molecular Weight Fractions

2009 ◽  
Vol 5 (1) ◽  
pp. 9-16 ◽  
Author(s):  
Jonhard Eysturskarð ◽  
Ingvild J. Haug ◽  
Ann-Sissel Ulset ◽  
Hóraldur Joensen ◽  
Kurt I. Draget
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Α Chain ◽  
Β Chain ◽  
Molecular Weight Fractions
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