scholarly journals Hydrocolloids in Dentistry: A Review

2021 ◽  
Author(s):  
Stanley Onwubu ◽  
Chibuzor Stellamaris Okonkwo
Keyword(s):  
Aqueous Solution ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Complex Material ◽  
And Storage

Hydrocolloids are complex polysaccharides that disperse or dissolve in aqueous solution to give thickened or vicious effects. Also hydrocolloids possess high molecular weight. Owing to these characteristics, hydrocolloids have been widely used in various applications. In dentistry, for example, most intricate and precise procedures are made of hydrocolloids and are found in its simplest material to the most complex material such as impression making, fillings, separating media, electro-polishing etc. The two common hydrocolloids widely used in dentistry are reversible (agar) and irreversible (alginate) materials. Hence, this chapter bring to the forefront their preparations, uses and storage for optimal results and application.

scholarly journals Speciation of chitosan with low and high molecular weight carboxylates in aqueous solution

2009 ◽  
Vol 21 (2) ◽  
pp. 81-91 ◽  
Author(s):  
Salvatore Cataldo ◽  
Concetta De Stefano ◽  
Antonio Gianguzza ◽  
Daniela Piazzese ◽  
Silvio Sammartano
Keyword(s):  
Aqueous Solution ◽  
Molecular Weight ◽  
High Molecular Weight

Conditions Affecting the Molecular Weight of Factor VIII.

1979 ◽  
Author(s):  
G. Rock ◽  
E. Tackaberry ◽  
D. Palmer
Keyword(s):  
Molecular Weight ◽  
Factor Viii ◽  
High Molecular Weight ◽  
Calcium Concentration ◽  
Low Molecular Weight ◽  
Biochemical Purification ◽  
Molecular Weights ◽  
Will Self ◽  
And Storage ◽  
Molecular Weight Form

By purifying Factor VIII while maintaining physiological concentrations of calcium we have recently demonstrated that about 50% of the procoagulant activity is in a very low molecular weight (VLHW) form not associated with the carrier (VIII: RAG). The remainder is carrier associated and elutes at Vo as a high molecular weight (HMW) compound upon Sepharose 6B chromatography. Reduction of the calcium concentration by increasing the amount of citrate added to heparin results in decreasing the ratio of VLMW:HMW from 1:1 in pure heparin to 1:5 in pure citrate. If citrate is replaced with the more strongly chelating EDTA no VLMW is detectable in the plasma. It has also been found that most of the biochemical purification techniques which have been previously used to prepare Factor VIII for study actually result in the aggregation of this VLMW with the carrier to produce the high molecular weight form. This includes: cryoprecipitation, precipitation by polyethylene glycol and storage -80°C. As well, the VLMW material will self-associate upon freezing to produce an aggregate with a molecular weight of 106. However, this material does not cross-react with rabbit antibody directed against VIII: RAG. The data indicate that many of the previously reported biochemical characteristics, including molecular weights, actually describe species which are artifacts of the isolation process rather than those of the physiologically occuring Factor VIII.

scholarly journals Stabilization of the front at frontal copolymerization of acrylamide with sodium acrylate in aqueous solutions

2020 ◽  
pp. 40-47
Author(s):  
Alena A. Salamevich ◽  
Yauheni V. Hryniuk ◽  
Leonid P. Krul
Keyword(s):  
Aqueous Solution ◽  
Molecular Weight ◽  
Aqueous Solutions ◽  
Water Absorption ◽  
High Molecular Weight ◽  
Frontal Polymerization ◽  
Sodium Acrylate ◽  
Initial Reaction ◽  
Initiator Concentration ◽  
Initial Reaction Mixture

The objects of research were the process of frontal copolymerization of acrylamide with sodium acrylate in aqueous solutions, as well as the copolymers and hydrogels thus obtained. It has been shown that the frontal polymerization of acrylamide with sodium acrylate in an aqueous solution of high molecular weight polyacrylamide helps to reduce the initiator concentration necessary for the process and the formation of non-crosslinked copolymers. The effect of the addition of aerosil in the initial reaction mixture on the parameters of the copolymerization process and on the properties of the products formed is studied. The values of water absorption and gel fractions of the obtained hydrogels were determined.

scholarly journals Aqueous copper(0) mediated reversible deactivation radical polymerization of 2-hydroxyethyl acrylate

2015 ◽  
Vol 6 (36) ◽  
pp. 6509-6518 ◽  
Author(s):  
Mingmin Zhang ◽  
Michael F. Cunningham ◽  
Robin A. Hutchinson
Keyword(s):  
Aqueous Solution ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Radical Polymerization ◽  
Reversible Deactivation ◽  
Reversible Deactivation Radical Polymerization

Lowering the concentration of adsorbed radicals on the Cu(0) surface, achieved by reducing catalyst and adding NaBr, is the key to the synthesis of well-defined P(HEA) without a high molecular weight shoulder in aqueous solution using two-step Cu(0)in situmediation.

scholarly journals Study of Interaction of Glycerol Cryoprotectant and Its Derivatives with Dimethylacetamide in Aqueous Solution Using Fluorescent Probes

2021 ◽  
Vol 31 (2) ◽  
pp. 139-150
Author(s):  
Tetiana Dyubko ◽  
◽  
Vasyl Pivovarenko ◽  
Valentina Chekanova ◽  
Yuliya Pakhomova ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Molecular Weight ◽  
High Molecular Weight ◽  
Fluorescent Probes ◽  
Low Molecular Weight ◽  
Polymerization Degree ◽  
Structural Rearrangements ◽  
Cryoprotective Agents ◽  
Molecular Associates ◽  
Derivatives Of

In this paper we have studied the interaction of the mixtures of glycerol (GL) and its oxyethylated derivatives (OEG) with polymerization degree n = 3, 25 and 30 with dimethylacetamide (DMAc) in aqueous solution using 3-hydroxy-4´-(N, N dimethylaminoflavone) fluorescent probe. The combination of GL and its oxyethylated derivatives with DMAc was found to reduce the membranotropy of certain cryoprotective agents, forming a mixture. The combination of both GL and its low molecular weight derivative (OEGn=3) with DMAc reduced the membranotropy of the latter. At the same time, combining GL derivatives of high molecular weight (OEGn=25 and OEGn=30) with DMAc diminished the membranotropy of OEG. The OEGn=30 at concentrations above 1 wt.% was shown to form the micellar-type structures or micellar associates in aqueous solution. This enabled suggesting the membranotropic ability of high molecular weight OEG associates to be stipulated by possible interaction of their nonpolar segments with nonpolar sites on biomembrane surface. Structural rearrangements of molecular associates in aqueous solutions of low and high molecular weight cryoprotectant mixtures were designated as the experimentally established mechanism of cytotoxicity reduction in combined cryoprotective media.

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