High and low molecular weight fractions of humic and fulvic acids

1977 ◽  
Vol 48 (1) ◽  
pp. 89-101 ◽  
Author(s):  
K. H. Tan
Keyword(s):  
Molecular Weight ◽  
Fulvic Acids ◽  
Low Molecular Weight ◽  
Humic And Fulvic Acids ◽  
Molecular Weight Fractions

scholarly journals Molecular-mass distribution of tundra soils humic substances from the European northeast of Russia

2015 ◽  
Author(s):  
Roman Vasilevitch ◽  
Evgeniy Lodygin ◽  
Vasiliy Beznosikov
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Molecular Mass Distribution ◽  
Weight Fraction ◽  
Fulvic Acids ◽  
Low Molecular Weight ◽  
Tundra Soils ◽  
Molecular Weight Fractions ◽  
Different Molecular Weight ◽  
A Share

It is established that the humic acids (HA) of tundra soils contain three fractions with a different molecular weight: ≥600, 62–83 and 2,6–5,3 kDa; fulvic acids (FA) — one fraction — 1,5–4,4 kDa. The maintenance of a low molecular weight fraction of HA considerably exceeds a share of medium and high molecular weight fractions. Reclamation of tundra surface-gley soils leads to decrease of a share of high molecular weight and to increase of a share of low molecular weight fraction as a part of HA. Correlative dependences between the contents of HA molecular weight fractions with parameters of HA are established. Refs 16. Figs 1. Tables 3.

Applications of Algal Polysaccharides and Derivatives in Therapeutic and Agricultural Fields

2019 ◽  
Vol 25 (11) ◽  
pp. 1187-1199 ◽  
Author(s):  
Soukaina Bouissil ◽  
Guillaume Pierre ◽  
Zainab El Alaoui-Talibi ◽  
Philippe Michaud ◽  
C. El Modafar ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Wound Dressing ◽  
Chemical Processes ◽  
Bioactive Molecules ◽  
Present Review ◽  
Agricultural Fields ◽  
Low Molecular Weight ◽  
Molecular Weight Fractions ◽  
Algal Polysaccharides ◽  
Agricultural Fertilizer

Background: Recently, researchers have given more and more consideration to natural polysaccharides thanks to their huge properties such as stability, biodegradability and biocompatibility for food and therapeutics applications. Methods: a number of enzymatic and chemical processes were performed to generate bioactive molecules, such as low molecular weight fractions and oligosaccharides derivatives from algal polysaccharides. Results: These considerable characteristics allow algal polysaccharides and their derivatives such as low molecular weight polymers and oligosaccharides structures to have great potential to be used in lots of domains, such as pharmaceutics and agriculture etc. Conclusion: The present review describes the mains polysaccharides structures from Algae and focuses on the currents agricultural (fertilizer, bio-elicitor, stimulators, signaling molecules and activators) and pharmaceutical (wound dressing, tissues engineering and drugs delivery) applications by using polysaccharides and/or their oligosaccharides derivatives obtained by chemical, physical and enzymatic processes.

Characterization of Elution Chromatography Fractions from CIS-Polybutadiene by GPC

1970 ◽  
Vol 43 (6) ◽  
pp. 1439-1450 ◽  
Author(s):  
W. V. Smith ◽  
S. Thiruvengada
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Low Molecular Weight ◽  
Molecular Weight Distributions ◽  
Weight Distributions ◽  
Log Normal ◽  
Analytical Fractionation ◽  
Molecular Weight Fractions ◽  
Elution Chromatography

Abstract A preparative fractionation of about 23 g of a commercial cis-polybutadiene rubber is described. The method employed was a solvent elution chromatographic method with very little temperature gradient. The molecular weight distributions of the fractions obtained were determined by an analytical fractionation of 20 mg of polymer. The method was similar to the preparative fractionation and involved solvent elution chromatography. The fractions obtained were assayed for quantity, molecular weight, and molecular weight distribution by GPC. The low molecular weight fractions of the preparative fractionation had molecular weight distributions which could be closely approximated by two log normal distributions, the low molecular weight component having the narrower width. The ratio of weight to number average molecular weight was found to be about 1.1 for these samples. The higher molecular weight fractions could also be approximated by two log normal distributions; however, in these fractions the low molecular weight component had a very broad distribution but constituted only a small portion of the sample. The widths of the GPC curves of the fractions correlate satisfactorily with the molecular weight distributions found by the analytical refractionations. The GPC width is a sensitive criterion of the width of the molecular weight distribution even when only two columns are used. It is felt that the analytical fractionation procedure presented gives more detailed information on the molecular weight distribution than is easily obtainable from an ordinary GPC curve.

Hepatic Metallothionein in Rainbow Trout (Salmo gairdneri) as an Indicator of Metal Pollution in the Campbell River System

1982 ◽  
Vol 39 (12) ◽  
pp. 1596-1601 ◽  
Author(s):  
M. Roch ◽  
J. A. McCarter ◽  
A. T. Matheson ◽  
M. J. R. Clark ◽  
R. W. Olafson
Keyword(s):  
Molecular Weight ◽  
Rainbow Trout ◽  
Metal Pollution ◽  
Quantitative Measure ◽  
Salmo Gairdneri ◽  
Differential Pulse Polarography ◽  
Low Molecular Weight ◽  
Gel Chromatography ◽  
Hepatic Metallothionein ◽  
Molecular Weight Fractions

Hepatic metallothionein was measured in livers of freshly killed rainbow trout (Salmo gairdneri) using differential pulse polarography. The fish were caught in metal-contaminated lakes of the Campbell River watershed and in a nearby control lake. The livers were analyzed for zinc, copper, and cadmium using atomic absorption spectrophotometry. High and low molecular weight protein fractions were separated by gel chromatography from liver cytosols and analyzed for metals. A downward trend from the most contaminated lake to the least was found in levels of zinc in the water, of cadmium and copper in high molecular weight fractions, and of copper in low molecular weight fractions and metallothionein. The concentration of metallothionein is a useful quantitative measure of the degree of exposure of fish to heavy metals.Key words: metallothionein, rainbow trout, Salmo gairdneri; heavy metal pollution, sublethal exposures, mine wastes

Postsynaptic block of a glutamatergic synapse by low molecular weight fractions of spider venom

1985 ◽  
Vol 339 (2) ◽  
pp. 237-244 ◽  
Author(s):  
A. Bateman ◽  
P. Boden ◽  
A. Dell ◽  
I.R. Duce ◽  
D.L.J. Quicke ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Spider Venom ◽  
Low Molecular Weight ◽  
Glutamatergic Synapse ◽  
Molecular Weight Fractions

scholarly journals Low-molecular weight fractions of Japanese soy sauce act as a RAGE antagonist via inhibition of RAGE trafficking to lipid rafts

2013 ◽  
Vol 4 (12) ◽  
pp. 1835 ◽  
Author(s):  
Seiichi Munesue ◽  
Yasuhiko Yamamoto ◽  
Ryouta Urushihara ◽  
Kouhei Inomata ◽  
Hidehito Saito ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Lipid Rafts ◽  
Soy Sauce ◽  
Low Molecular Weight ◽  
Molecular Weight Fractions

Size fractionation characterisation of removed organics in reverse osmosis concentrates by ferric chloride

2011 ◽  
Vol 63 (9) ◽  
pp. 1795-1800 ◽  
Author(s):  
A. Y. Bagastyo ◽  
J. Keller ◽  
D. J. Batstone
Keyword(s):  
Molecular Weight ◽  
Reverse Osmosis ◽  
Ferric Chloride ◽  
Membrane Separation ◽  
Fulvic Acids ◽  
Cell System ◽  
Humic And Fulvic Acids ◽  
Stirred Cell ◽  
Almost All ◽  
Reverse Osmosis Concentrates

Reverse osmosis membrane separation is the leading method for manufacturing potable purified water. It also produces a concentrate stream, namely reverse osmosis concentrates (ROC), with 10–20% of the water, and almost all other compounds. One method for further treating this stream is by coagulation with ferric chloride. This study evaluates removed organics in ROC treated with ferric chloride. Fractionation with ultrafiltration membranes allows separation of organics based on a nominal molecular weight. A stirred cell system was applied for serial fractionation to classify organic compounds into six groups of <0.5 kDa, 0.5–1 kDa, 1–3 kDa, 3–5 kDa, 5–10 kDa and >10 kDa. The study found that raw ROC is rich in low molecular weight compounds (<1 kDa) with almost 50% of the organics. These compounds include soluble microbial products (SMPs) and smaller humic and fulvic acids as indicated by fluorescence scanning. Conversely, colour was mostly contributed by medium to large molecules of humic and fulvic acids (>0.5 kDa). Organics and colour were reduced in all molecular groups at an optimum treatment dose 1.48 mM FeCl3 and a pH of 5. However, ferric seemed to effectively remove colour in all size ranges while residual nitrogen was found mostly in the <1 kDa sizes. Further, the fluorescence indicated that larger humic and fulvic acids were removed with considerable SMPs remaining in the <0.5 kDa.

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