A quantitative analysis of the supercontraction-induced molecular disorientation of major ampullate spider silk

We show detailed understanding of enzyme dependent structural changes in supercoiled DNA along with a quantitative analysis of its branches using nanopores.

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Application of Infrared Absorption Spectra to Studies of the Oxidation of Sodium-Butadiene Rubber

Rubber Chemistry and Technology ◽

10.5254/1.3543088 ◽

1951 ◽

Vol 24 (3) ◽

pp. 591-596

Author(s):

B. Dogadkin ◽

B. Kasatochkin ◽

N. Klauzen ◽

A. Smirnova

Keyword(s):

Quantitative Analysis ◽

Molecular Oxygen ◽

Structural Changes ◽

Chemical Properties ◽

Butadiene Rubber ◽

Physical And Chemical Properties ◽

Reaction Products ◽

Infrared Absorption Spectra ◽

Physical And Chemical ◽

And Chemical Properties

Abstract The reaction of rubber with molecular oxygen explains well the structural changes which take place in rubber during aging and during a number of important technological processes, such as plasticization and vulcanization. Furthermore, during vulcanization, in addition to its reaction with the vulcanizing agent, rubber also reacts with oxygen contained in the mixture. This may be one of the reasons for an optimum point of vulcanization. However, it is difficult to explain the changes of physical properties of rubber by simple union of oxygen, with formation of oxygen-bearing groups. To account for the changes observed, addition of a large quantity of oxygen would be necessary, whereas actually notable changes are brought about by the absorption of only 2–3 per cent of oxygen. To explain this, it must be assumed that oxygen causes structural changes in rubber and that these changes become evident when the percentage of oxygen in the reaction products is still negligible. In the case of sodium-butadiene rubber, as was shown by one of the authors, this reaction at any particular temperature causes an increase of strength and of elasticity, and a loss of solubility. The object of the present investigation was a qualitative and limited quantitative analysis of those groups which originate during oxidation and also an examination of the structures which determine the changes of the physical and chemical properties in the reaction of rubber with molecular oxygen.

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Automated Sectoral Quantitative Analysis of Parafoveal Microvascular Status and Association with Structure in Diabetic Macular Edema

10.21203/rs.3.rs-561485/v1 ◽

2021 ◽

Author(s):

Nihat Polat ◽

Saim Yoloğlu

Keyword(s):

Quantitative Analysis ◽

Macular Edema ◽

Diabetic Macular Edema ◽

Structural Changes ◽

Vessel Density ◽

External Limiting Membrane ◽

Ellipsoid Zone ◽

Capillary Plexus ◽

Temporal Quadrant ◽

Superficial Capillary Plexus

Abstract Purpose: To evaluate the integrity of the capillary plexuses, their relationship with each other, and their association with structural changes in a sectoral manner in diabetic macular edema (DME).Methods: The vessel density (VD) was measured in inferior, superior, nasal and temporal (İ, S, N, T) parafovea in the superficial capillary plexus (SCP) and deep capillary plexus (DCP). The integrity of the external limiting membrane (ELM) and ellipsoid zone (EZ) were evaluated in B-scan images.Results: In the SCP, only superior and nasal VD was significantly lower (P: 0.0001 and P: 0.020, respectively) while in the DCP, only temporal VD was significantly lower in the DME eyes (P: 0.034). There was no correlation between the VD of SCP and DCP in the corresponding quadrants (all P > 0.05). The FAZ area was significantly greater (both superficial and deep) in DME eyes than in control eyes (P > 0.05). ELM disruptions were not affected by the corresponding VDs in the SCP (all P> 0.05), but nasal and temporal quadrant ELM disruptions were affected by VDs in the DCP in the corresponding quadrants (P: 0.005 nasal, P: 0.001 temporal). EZ disruptions were not affected by the corresponding VDs in the SCP and DCP (all P> 0.05).Conclusions: The SCP was affected in more quadrants than the DCP and probably independently from each other. There was an association with the ELM and the DCP, especially in nasal and temporal quadrants, but there was not an association between the EZ and SCP or DCP.

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