Results 231 to 240 of about 29,572 (274)

On the mechanism of collapse of monolayers of macromolecular substances II. Cellulose acetate

Journal of Colloid and Interface Science, 1980
Abstract The phenomenon of collapse of monolayers of cellulose acetate, describable according to the Prout-Tompkins law, that is as a phenomenon of nucleation and growth with interference during growth, was studied. Ellipsometric measurements and measurements made by optical and electronic microscopy confirm the above mechanism.
Piero Baglioni, Giulio G. T. Guarini, Gabriella Gabrielli   +2 more
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Macromolecular material (humic substance) in the water column and sediments

Marine Chemistry, 1992
Abstract The progress during the past 10–15 years in the studies of organic macromolecules (humic substances, HS) in seawater and sediments is reviewed. The review describes the advances in the characterization of seawater and sedimentary HS, HS formation models, studies on the geochemical role of marine HS, and future research needs.
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The interrelationship among bradykinin, various vasoactive substances, and macromolecular permeability in the canine forelimb

Microvascular Research, 1980
Abstract Bradykinin (0.8 μg base/min) infused locally intraarterially into canine forelimbs perfused at constant inflow causes marked increases in lymph flow rate and lymph total protein concentration. This same dose of bradykinin infused locally intraarterially for 60 min into forelimbs perfused at constant inflow with vasopressin (0.8 P.U./min) or ...
Bhagavan S. Jandhyala, Richard M. Raymond, George J. Grega   +2 more
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Modes of Absorption of Macromolecular Substances

1995
When we speak about absorption of macromolecular substances we must take into consideration the barriers of the gastrointestinal tract which hinder their uptake and transportation into the lymphatics and the blood. These barriers can be differentiated into morphological and functional barriers.
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On the mechanism of collapse of monolayers of macromolecular substances: poly(l, d, and dl)alanine

Journal of Colloid and Interface Science, 1981
Abstract The collapse process of monolayers of poly( l , d , dl )alanine has been studied at the air—water interface, and on substrates containing Ca2+, Na+, and K+. It is demonstrated that the collapse process occurs in two stages. The first, attributable to a process of nucleation, is related to the detachment of the polymeric chains from the ...
GABRIELLI, GABRIELLA, BAGLIONI, PIERO, FERRONI, ENZO   +2 more
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MACROMOLECULAR PROPERTIES OF SOIL HUMIC SUBSTANCES: FACT, FICTION, AND OPINION

Soil Science, 1999
A critical review of 'random coil' and 'self-associating aggregate' models and of earlier concepts of the macromolecular structure of humic substances (HS) is undertaken as a result of the development of more recent information and hypotheses.
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AGGREGATION PATTERNS AND MACROMOLECULAR MORPHOLOGY OF HUMIC SUBSTANCES: A FRACTAL APPROACH

Soil Science, 1999
Fractal geometry provides a powerful means for the quantitative description of heterogeneous and highly irregular systems encountered in nature. Humic substances represent a typical class of natural compounds that may be amenable to a fractal description because of their well known physical and chemical heterogeneity and molecular complexity.
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Proton magnetic resonance studies on water in the presence of various macromolecular substances

Journal of Molecular Biology, 1959
Because of the magnetic properties associated with atomic nuclei, it is possible to measure the absorption of electromagnetic radiation (40–60 Mc/s) by protons when a sample is placed in a strong magnetic field (10,000–15,000 gauss). By keeping the radio-frequency constant and varying the magnetic field an absorption curve having a maximum at the so ...
Aksel A. Bothner-By, Aksel A. Bothner-By, Aksel A. Bothner-By, John Gergely, John Gergely, John Gergely, Endre A. Balazs, Endre A. Balazs, Endre A. Balazs   +8 more
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Synthesis of Macromolecular Substances by Condensation Polymerization and Stepwise Addition Polymerization

2001
Condensation polymerizations (polycondensations) are stepwise reactions between bifunctional or polyfunctional components, with elimination of simple molecules such as water or alcohol and the formation of macromolecular substances. For the preparation of linear condensation polymers from bifunctional compounds (the same considerations apply to ...
Helmut Ritter, h.c. Dietrich Braun, Harald Cherdron   +2 more
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Deep eutectic solvent: Synthesis, classification, properties and application in macromolecular substances

International Journal of Biological Macromolecules
Deep eutectic solvent (DES) is a kind of solvent prepared by mixing hydrogen bond donors and hydrogen bond acceptors, and have become a hot topic in ecological civilization construction due to its low toxicity and sustainability. Its excellent properties such as low volatility, thermal stability and biodegradability make it stand out among many organic
Yuying, Gao, Min, Fan, Xiaoxiao, Cheng, Xiaofang, Liu, Hui, Yang, Wenya, Ma, Min, Guo, Li, Li   +7 more
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