Frozen State of Sephadex
| Autor: | Norio Murase, Toshio Kawahara, Kentaro Irie, Yuki Uetake, Sato Yuki, Toru Hirauchi, Mitsuhiro Hirai, Ueno Yohei |
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| Rok vydání: | 2018 |
| Předmět: |
Diffraction
Materials science Polymers and Plastics XRD Analytical chemistry crosslink density (density of crosslinks) Bioengineering 010402 general chemistry 01 natural sciences Article law.invention Biomaterials ice crystallization during rewarming Sephadex® (crosslinked dextran) ice grain glassy water X-ray CT law X ray computed 0103 physical sciences Crystallization 010304 chemical physics Ice crystals Organic Chemistry Synchrotron 0104 chemical sciences Amorphous ice X-ray crystallography Tomography |
| Zdroj: | Gels; Volume 4; Issue 2; Pages: 44 Gels |
| ISSN: | 2310-2861 |
| Popis: | Water in Sephadex® (crosslinked dextran) gels is known to indicate different freezing behavior which is dependent on the density of the crosslinks, and water in a Sephadex® G25 gel remains partially unfrozen during cooling and crystallizes during rewarming. The mechanism of anomalous ice crystallization during rewarming is still unclear. The objective of this study is to observe the ice grains that form in Sephadex® beads and to comprehend their frozen state with a focus on the ice crystallization during rewarming. Sephadex® beads containing 50 wt % water were prepared and used for the measurements. The observation of the ice grains was carried out by using synchrotron radiation-sourced X-ray CT (computed tomography). XRD (X-ray diffraction) analysis was also conducted to investigate the frozen state. As a result, ice grains that were larger than ~1 μm were hardly observed after the slow cooling of Sephadex® beads, except in the G25 beads. However, at the occurrence of ice crystallization during rewarming, ice grains that were larger than 10 μm appeared in the G25 beads. Using XRD, it was found that small incomplete ice crystals were formed in G25 beads and the presence of glassy water was indicated in the gel. In conclusion, the size and distribution of ice grains that formed in Sephadex® beads were different depending on the density of the crosslinks. |
| Databáze: | OpenAIRE |
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