Characterisation and effects of new anionic groups formed during chemithermomechanical pulping of spruce

2007 ◽  
Vol 296 (1-3) ◽  
pp. 1-7 ◽  
Author(s):  
Jonas Konn ◽  
Andrey Pranovich ◽  
Pedro Fardim ◽  
Bjarne Holmbom
Keyword(s):  
Chemithermomechanical Pulping ◽  
Anionic Groups

Some triphenyltin(IV) complexes containing potentially bidentate, biologically active anionic groups

1992 ◽  
Vol 436 (2) ◽  
pp. 155-167 ◽  
Author(s):  
Bruce D. James ◽  
Sam Gioskos ◽  
Shubhra Chandra ◽  
Robert J. Magee ◽  
John D. Cashion
Keyword(s):  
Biologically Active ◽  
Anionic Groups

Role of cations in the flocculation of Saccharomyces cerevisiae and discrimination of the corresponding proteins

1991 ◽  
Vol 37 (5) ◽  
pp. 397-403 ◽  
Author(s):  
Hiroshi Kuriyama ◽  
Itaru Umeda ◽  
Harumi Kobayashi
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Surface ◽  
Inhibitory Effect ◽  
Surface Proteins ◽  
Promoting Effect ◽  
Yeast Strains ◽  
Yeast Flocculation ◽  
Different Types ◽  
Anionic Groups

Asexual yeast flocculation was studied using strong flocculents of Saccharomyces cerevisiae. The inhibitory effect of cations on flocculation is considered to be caused by competition between those cations and Ca2+ at the binding site of the Ca2+-requiring protein that is involved in flocculation. Inhibition of flocculation by various cations occurred in the following order: La3+, Sr2+, Ba2+, Mn2+, Al3+, and Na+. Cations such as Mg2+, Co2+, and K+ promoted flocculation. This promoting effect may be based on the reduction of electrostatic repulsive force between cells caused by binding of these cations anionic groups present on the cell surface. In flocculation induced by these cations, trace amounts of Ca2+ excreted on the cell surface may activate the corresponding protein. The ratio of Sr2+/Ca2+ below which cells flocculated varied among strains: for strains having the FLO5 gene, it was 400 to 500; for strains having the FLO1 gene, about 150; and for two alcohol yeast strains, 40 to 50. This suggests that there are several different types of cell surface proteins involved in flocculation in different yeast strains. Key words: yeast, flocculation, protein, cation, calcium.

scholarly journals THE CHEMICAL NATURE OF MACROPHAGE RNA-ANTIGEN COMPLEXES AND THEIR RELEVANCE TO IMMUNE INDUCTION

1969 ◽  
Vol 130 (3) ◽  
pp. 557-574 ◽  
Author(s):  
Georges E. Roelants ◽  
Joel W. Goodman
Keyword(s):  
Amino Acids ◽  
Complex Formation ◽  
Chemical Nature ◽  
Divalent Cations ◽  
Chelating Agent ◽  
Total Absence ◽  
Synthetic Polypeptides ◽  
Antigen Complex ◽  
Anionic Groups ◽  
Do So

10 different compounds, including natural and synthetic polypeptides, proteins, polysaccharides, amino acids, and steroid hormones, were assayed for their capacity to form complexes with peritoneal exudate cell RNA. Only molecules carrying negatively charged groups were able to do so. The formation of RNA-antigen complexes was unrelated to the immuno-potency of the "antigen," was not an enzyme-dependent reaction, did not require the synthesis of RNA following introduction of the antigen, did not seem to involve antigen-specific RNAs, was not specific for macrophages, since HeLa cells could be used as effectively, and occurred when purified RNA was mixed with antigen only in the presence of divalent cations. The complexes were very stable, once formed, but could be dissociated by exhaustive dialysis against buffers containing a chelating agent. The macrophage RNA-antigen complex therefore appears to be a chelate between anionic groups on the two components. Based on the total absence of a relationship between immunogenicity and the capacity to form such complexes, as well as the nonspecific nature of complex formation at every level examined, it appears unlikely that RNA-antigen complexes play a physiologically significant role in immune induction.

Cation exchange in cell walls of gram-positive bacteria

1976 ◽  
Vol 22 (7) ◽  
pp. 975-982 ◽  
Author(s):  
Robert E. Marquis ◽  
Kathleen Mayzel ◽  
Edwin L. Carstensen
Keyword(s):  
Cation Exchange ◽  
Cell Walls ◽  
Divalent Cations ◽  
Teichoic Acid ◽  
Dry Weight ◽  
High Ionic Strength ◽  
Monovalent Cations ◽  
Anionic Sites ◽  
Gram Positive Bacteria ◽  
Anionic Groups

The relative affinities of various cations for anionic sites in isolated, bacterial cell walls were assessed by means of a technique involving displacement of one cation by another. The affinity series determined was [Formula: see text]. High affinity was correlated with low mobility of the bound ions in an electric field. The net cation-exchange capacities of walls isolated from a variety of bacteria were estimated by preparing the magnesium forms of the walls, washing them well with deionized water to remove supernumerary ions, and then completely displacing the magnesium with Na+ or H+. Total amounts of magnesium displaced varied from 73 μmol per gram dry weight, for walls of the teichoic acid-deficient 52A5 strain of Staphylococcus aureus to about 520 μmol per gram for Bacillus megaterium KM walls. The amount of displacable magnesium was inversely related to the physical compactness of the walls, except for walls of Streptococcus mutans GS-5. It was found that magnesium or calcium ions can each neutralize, or pair with, two anionic groups in walls suspended in ion-deficient media. Previous work had indicated that these ions may pair with only one anionic group at high ionic strength. Therefore, it appeared that there is a great deal of flexibility in the arrangement of charged groups in the wall. It was concluded also that for cells growing in commonly used laboratory media, which generally contain large excesses of monovalent versus divalent cations, there is a mix of small, cationic counterions in the wall and that monovalent cations may predominate even though the wall has higher affinity for divalent ions.

scholarly journals Recent Advances in Zwitterionic Hydrogels: Preparation, Property, and Biomedical Application

Gels ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 46
Author(s):  
Sihang Liu ◽  
Jingyi Tang ◽  
Fangqin Ji ◽  
Weifeng Lin ◽  
Shengfu Chen
Keyword(s):  
Immune System ◽  
Polyethylene Glycol ◽  
Biomedical Applications ◽  
Biomedical Application ◽  
Synthetic Polymers ◽  
Human Environment ◽  
The Past ◽  
Recent Advances ◽  
Nonspecific Protein Adsorption ◽  
Anionic Groups

Nonspecific protein adsorption impedes the sustainability of materials in biologically related applications. Such adsorption activates the immune system by quick identification of allogeneic materials and triggers a rejection, resulting in the rapid failure of implant materials and drugs. Antifouling materials have been rapidly developed in the past 20 years, from natural polysaccharides (such as dextran) to synthetic polymers (such as polyethylene glycol, PEG). However, recent studies have shown that traditional antifouling materials, including PEG, still fail to overcome the challenges of a complex human environment. Zwitterionic materials are a class of materials that contain both cationic and anionic groups, with their overall charge being neutral. Compared with PEG materials, zwitterionic materials have much stronger hydration, which is considered the most important factor for antifouling. Among zwitterionic materials, zwitterionic hydrogels have excellent structural stability and controllable regulation capabilities for various biomedical scenarios. Here, we first describe the mechanism and structure of zwitterionic materials. Following the preparation and property of zwitterionic hydrogels, recent advances in zwitterionic hydrogels in various biomedical applications are reviewed.

Chemithermomechanical pulping of white birch for newsprint

1984 ◽  
Vol 14 (4) ◽  
pp. 488-492
Author(s):  
K. N. Law ◽  
P. Rioux ◽  
M. Lapointe ◽  
J. L. Valade
Keyword(s):  
Partial Replacement ◽  
White Birch ◽  
Paper Properties ◽  
Chemical Pulp ◽  
Chemithermomechanical Pulping

The main objective of the study was to investigate the mechanical pulping characteristics of white birch (Betulapapyrifera Marsh.) by a chemithermomechanical process using NaOH and Na2SO3 in the pretreatment of chips prior to pressurized refining. The results indicated that the NaOH had significant effect upon the pulp quality, whereas the Na2SO3 was of limited importance. Chemithermomechanical pulp of white birch was further found to be suitable for at least partial replacement of high-cost chemical pulp component, customarily added to newsprint furnishes, without lowering of paper properties.

Sign in / Sign up

Export Citation Format

Share Document