scholarly journals Influence of the content of n-butanol on the critical conversion of gel formation during “living” three-dimensional radical co-polymerization of styrene and divinylbenzene

2019 ◽  
Vol 525 ◽  
pp. 012025
Author(s):  
R I Komendant ◽  
E O Perepelitsina ◽  
S A Kurochkin
Keyword(s):  
Three Dimensional ◽  
Gel Formation ◽  
Critical Conversion

scholarly journals Effect of Sodium Caseinates Addition on the Rheological Properties of Kefir during Gel Formation

2016 ◽  
Vol 5 (1) ◽  
pp. 114
Author(s):  
Kleio D. Antoniou ◽  
Stylianos Exarhopoulos ◽  
Stylianos N. Raphaelides ◽  
Georgia Dimitreli ◽  
Apostolos S. Thomareis
Keyword(s):  
Elastic Modulus ◽  
Loss Tangent ◽  
Protein Interactions ◽  
Ph Value ◽  
Bovine Milk ◽  
Three Dimensional ◽  
Fermented Milk ◽  
Elastic Behavior ◽  
Gel Formation ◽  
Fermentation Time

The effect of Sodium Caseinates (SCN) addition on the rheological behavior of kefir during gel formation was monitored by means of a dynamic rheometer of novel design (U-tube Rheometer). Kefir samples were prepared from homogenized and pasteurized full fat (3.5% w/w) bovine milk with or without the addition of SCN at varying concentrations (1%, 2% or 3% w/w). A fermented milk inoculum derived from kefir grains was inoculated into the heat-treated milk and incubated at 25°C until the pH dropped to 4.6. According to the results, the fermentation time required for the onset of gelation, as well as for the pH value to reach 4.6 increased with increasing SCN concentration. The beginning of cross-linking of proteins towards aggregates that leads to the formation of a three-dimensional protein matrix, took place at higher pH values with increasing SCN concentration. The values of elastic modulus and loss tangent that correspond to this point decreased with increasing SCN content. The increase in SCN concentration caused the values of elastic modulus during gel formation to increase and those of loss tangent to decrease. The addition of caseins into the milk increased the number and the strength of the protein-protein interactions causing the elastic behavior of the samples to increase. The presence of SCN into the system of kefir greatly affected the formation of the kefir gel.

Modification of an Injectable Chitosan Scaffold by Blending with NaHCO3 to Improve Cytocompatibility

2011 ◽  
Vol 19 (9) ◽  
pp. 781-788 ◽  
Author(s):  
Zhi Huang ◽  
Bo Yu ◽  
Qingling Feng ◽  
Songjian Li
Keyword(s):  
Body Temperature ◽  
Room Temperature ◽  
Three Dimensional ◽  
Chitosan Solution ◽  
Gel Formation ◽  
Injectable Scaffolds ◽  
Injectable Scaffold ◽  
Porous Hydrogel ◽  
Scanning Electron

The chitosan/β-glycerophosphate (C/GP) system, which allows injection at room temperature and gel-formation at body temperature, can be considered as a candidate for injectable scaffolds. To improve the cytocompatiblity of the C/GPhydrogel, we used NaHCO3 as buffer to neutralize chitosan solution and lower the GP concentration from 400 to 135 mM. The chitosan/β-glycerophosphate//NaHCO3 (C/GP/NaHCO3) system was liquid before injection and became a three-dimensional porous hydrogel at body temperature, as revealed by scanning electron microscopy (SEM). The C/GP/NaHCO3 hydrogels showed higher cytocompatibility with rat bone marrow-derived mesenchymal stem cells (rBMSCs) in vitro compared to C/GP hydrogels. Our results indicated that the C/GP/NaHCO3 system was suitable as an injectable scaffold for tissue engineering.

Critical conversion during three-dimensional living copolymerization

2011 ◽  
Vol 53 (7-8) ◽  
pp. 427-430 ◽  
Author(s):  
T. F. Irzhak ◽  
V. I. Irzhak
Keyword(s):  
Three Dimensional ◽  
Critical Conversion

The orbit of Pluto over a long interval of time

1966 ◽  
Vol 25 ◽  
pp. 227-229 ◽  
Author(s):  
D. Brouwer
Keyword(s):  
Periodic Orbit ◽  
Numerical Integration ◽  
Restricted Problem ◽  
Three Dimensional ◽  
The Third ◽  
Circular Restricted Problem ◽  
Resonance Relation

The paper presents a summary of the results obtained by C. J. Cohen and E. C. Hubbard, who established by numerical integration that a resonance relation exists between the orbits of Neptune and Pluto. The problem may be explored further by approximating the motion of Pluto by that of a particle with negligible mass in the three-dimensional (circular) restricted problem. The mass of Pluto and the eccentricity of Neptune's orbit are ignored in this approximation. Significant features of the problem appear to be the presence of two critical arguments and the possibility that the orbit may be related to a periodic orbit of the third kind.

Conformation of Ribosomes from Escherichia Coli

1974 ◽  
Vol 32 ◽  
pp. 210-211
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Binding Sites ◽  
Ribosomal Proteins ◽  
Fluorescent Dyes ◽  
Protein Biosynthesis ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Dimensional Structure ◽  
Complete Understanding ◽  
And Function

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.

Ultrastructural Investigations of the Contractile Filaments of Amoebae

1974 ◽  
Vol 32 ◽  
pp. 188-189
Author(s):  
P.L. Moore
Keyword(s):  
Cytoplasmic Streaming ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Amoeboid Movement ◽  
Different Types ◽  
Chemical Conditions ◽  
Complete Interpretation

Previous freeze fracture results on the intact giant, amoeba Chaos carolinensis indicated the presence of a fibrillar arrangement of filaments within the cytoplasm. A complete interpretation of the three dimensional ultrastructure of these structures, and their possible role in amoeboid movement was not possible, since comparable results could not be obtained with conventional fixation of intact amoebae. Progress in interpreting the freeze fracture images of amoebae required a more thorough understanding of the different types of filaments present in amoebae, and of the ways in which they could be organized while remaining functional.The recent development of a calcium sensitive, demembranated, amoeboid model of Chaos carolinensis has made it possible to achieve a better understanding of such functional arrangements of amoeboid filaments. In these models the motility of demembranated cytoplasm can be controlled in vitro, and the chemical conditions necessary for contractility, and cytoplasmic streaming can be investigated. It is clear from these studies that “fibrils” exist in amoeboid models, and that they are capable of contracting along their length under conditions similar to those which cause contraction in vertebrate muscles.

Structural organization of escherichia coli ribosomes as determined by immuno electron microscopy

1978 ◽  
Vol 36 (2) ◽  
pp. 166-167 ◽  
Author(s):  
G. Stöffler ◽  
R.W. Bald ◽  
J. Dieckhoff ◽  
H. Eckhard ◽  
R. Lührmann ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Ribosomal Proteins ◽  
Structural Organization ◽  
Three Dimensional ◽  
Ribosomal Subunit ◽  
Spatial Arrangement ◽  
Small Subunit ◽  
Antibody Binding ◽  
Immuno Electron Microscopy

A central step towards an understanding of the structure and function of the Escherichia coli ribosome, a large multicomponent assembly, is the elucidation of the spatial arrangement of its 54 proteins and its three rRNA molecules. The structural organization of ribosomal components has been investigated by a number of experimental approaches. Specific antibodies directed against each of the 54 ribosomal proteins of Escherichia coli have been performed to examine antibody-subunit complexes by electron microscopy. The position of the bound antibody, specific for a particular protein, can be determined; it indicates the location of the corresponding protein on the ribosomal surface.The three-dimensional distribution of each of the 21 small subunit proteins on the ribosomal surface has been determined by immuno electron microscopy: the 21 proteins have been found exposed with altogether 43 antibody binding sites. Each one of 12 proteins showed antibody binding at remote positions on the subunit surface, indicating highly extended conformations of the proteins concerned within the 30S ribosomal subunit; the remaining proteins are, however, not necessarily globular in shape (Fig. 1).

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