Dataset Information

Relaxation dynamics in the strong chalcogenide glass-former of Ge₂₂Se₇₈.

ABSTRACT: The enthalpy relaxation is performed in the glassy Ge₂₂Se₇₈ to understand the dynamic behaviors. The structure of the glass is examined by X-ray diffraction and Raman spectra. The dynamic parameters such as the fragility, stretching exponent and non-linear factor are determined. A low fragility of m = 27 is exhibited for the chalcogenide, however, the stretching exponent is found not to have a larger value. The enthalpy relaxation spectra are constructed for various glass formers, and a relationship between the fragility and the symmetry of the spectra is demonstrated. The dynamic results are used to evaluate the structure of the Ge₂₂Se₇₈ glass.

SUBMITTER: Li P

PROVIDER: S-EPMC5240093 | biostudies-literature | 2017 Jan

REPOSITORIES: biostudies-literature

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Publications

Relaxation dynamics in the strong chalcogenide glass-former of Ge22Se78.

Li Pengfei P Zhang Yaqi Y Chen Zeming Z Gao Peng P Wu Tao T Wang Li-Min LM

Scientific reports 20170117

The enthalpy relaxation is performed in the glassy Ge22Se78 to understand the dynamic behaviors. The structure of the glass is examined by X-ray diffraction and Raman spectra. The dynamic parameters such as the fragility, stretching exponent and non-linear factor are determined. A low fragility of m = 27 is exhibited for the chalcogenide, however, the stretching exponent is found not to have a larger value. The enthalpy relaxation spectra are constructed for various glass f ...[more]

PMID: 28094287

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Project description:In vivo cancer detection based on the mid-infrared molecular fingerprint of tissue is promising for the fast diagnosis and treatment of suspected cancer patients. Few materials are mid-infrared transmissive, even fewer, which can be converted into functional, low-loss optical fibres for in vivo non-invasive testing. Chalcogenide-based glass optical fibres are, however, one of the few. These glasses are transmissive in the mid-infrared and are currently under development for use in molecular sensing devices. The cytotoxicity of these materials is however unknown. The cytotoxicity of Ge-Sb-Se chalcogenide optical glass fibres on 3T3 mouse fibroblast cells is here investigated. Fibres exposed to four different pre-treatment conditions are used: as-drawn (AD), propylamine-etched (PE), oxidised-and-washed (OW) and oxidised (Ox). To achieve the latter two conditions, fibres are treated with H2O2(aqueous (aq.)) and dried to produce a surface oxide layer; this is either washed off (OW) or left on the glass surface (Ox). Cellular response is investigated via 3 day elution and 14 day direct contact trials. The concentration of the metalloids (Ge, Sb and Se) in each leachate was measured via inductively coupled plasma mass spectrometry. Cell viability is assessed using the neutral red assay and scanning electron microscopy. The concentration of Ge, Sb and Se ions after a 3 day dissolution was as follows. In AD leachates, Ge: 0.40 mg L-1, Sb: 0.17 mg L-1, and Se: 0.06 mg L-1. In PE leachates, Ge: 0.22 mg L-1, Sb: 0.15 mg L-1, and Se: 0.02 mg L-1. In Ox leachates, Ge: 823.8 mg L-1, Sb: 2586.6 mg L-1, and Se: 3750 mg L-1. Direct contact trials show confluent cell layers on AD, PE and OW fibres after 14 days, while no cells are observed on the Ox surfaces. A >50% cell viability is observed in AD, PE and OW eluates after 3 days, when compared with Ox eluates (<10% cell viability). Toxicity in Ox is attributed to the notable pH change, from neutral pH 7.49 to acidic pH 2.44, that takes place on dissolution of the surface oxide layer in the growth media. We conclude, as-prepared Ge-Sb-Se glasses are cytocompatible and toxicity arises when an oxide layer is forced to develop on the glass surface.

Dataset Information

Relaxation dynamics in the strong chalcogenide glass-former of Ge₂₂Se₇₈.

Publications

Relaxation dynamics in the strong chalcogenide glass-former of Ge<sub>22</sub>Se<sub>78</sub>.

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