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Estimation for diameter of superparamagnetic particles in Daphnia resting eggs

View Article: PubMed Central - PubMed

ABSTRACT

Ferromagnetic resonance (FMR) with an electron spin resonance (ESR) apparatus was investigated for super-paramagnetic particles within Daphnia resting eggs. High-field (HF) resonance lines near g=2 resulted from single superparamagnetic particles, were detected from ESR spectra of Daphnia resting eggs. The size of isolated superparamagnetic particles within Daphnia resting eggs was calculated to be approximately 13 nm in diameter by analysis of the temperature dependence of the HF line width. Small-angle X-ray scattering (SAXS) analysis of Daphnia resting eggs also showed that average size of superparamagnetic particles in diameter, equivalent to magnetite, was approximately 13 nm. The combination of FMR and SAXS measurement is very effective in estimating the size of superparamagnetic particles in biological organisms, with difficulties of preparing for samples for measurement by electron microscopy. However, Chlorella, with that Daphnia were raised, did not show FMR spectra, showing no magnetic particles within Daphnia resting eggs. Therefore, it suggested that superparamagnetic particles within Daphnia resting eggs, were mineralized in Daphnia as the result of biomineralization of Fe originated from Chlorella.

No MeSH data available.


ESR spectra on Daphnia resting eggs measured at 88 K. ESR spectra of Daphnia resting eggs at 88K divided into narrow (C1) line and broader (C2) line with Gaussian function. A combined line with narrow and broad components, showing a good fitting with an experimental result.
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f2-6_53: ESR spectra on Daphnia resting eggs measured at 88 K. ESR spectra of Daphnia resting eggs at 88K divided into narrow (C1) line and broader (C2) line with Gaussian function. A combined line with narrow and broad components, showing a good fitting with an experimental result.

Mentions: A similar analysis of the spectra by Gaussian fitting was performed for interpreting the signal C of Daphnia resting eggs. Figure 2 shows the result of Gaussian fitting of the signal C at 88 K divided into a narrow (C1) line and a broad (C2) line. The line shape around g = 2 in Figure 2 is well reproduced by the sum of two Gaussian curves of C1 line and C2 line. C2 were divided from ESR spectra at all measurement temperatures, showing increasing its intensity and narrowing its line width with temperature increasing. This C2 behavior is characteristic of FMR. Therefore, C2 is equivalent to HF line.


Estimation for diameter of superparamagnetic particles in Daphnia resting eggs
ESR spectra on Daphnia resting eggs measured at 88 K. ESR spectra of Daphnia resting eggs at 88K divided into narrow (C1) line and broader (C2) line with Gaussian function. A combined line with narrow and broad components, showing a good fitting with an experimental result.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC5036663&req=5

f2-6_53: ESR spectra on Daphnia resting eggs measured at 88 K. ESR spectra of Daphnia resting eggs at 88K divided into narrow (C1) line and broader (C2) line with Gaussian function. A combined line with narrow and broad components, showing a good fitting with an experimental result.
Mentions: A similar analysis of the spectra by Gaussian fitting was performed for interpreting the signal C of Daphnia resting eggs. Figure 2 shows the result of Gaussian fitting of the signal C at 88 K divided into a narrow (C1) line and a broad (C2) line. The line shape around g = 2 in Figure 2 is well reproduced by the sum of two Gaussian curves of C1 line and C2 line. C2 were divided from ESR spectra at all measurement temperatures, showing increasing its intensity and narrowing its line width with temperature increasing. This C2 behavior is characteristic of FMR. Therefore, C2 is equivalent to HF line.

View Article: PubMed Central - PubMed

ABSTRACT

Ferromagnetic resonance (FMR) with an electron spin resonance (ESR) apparatus was investigated for super-paramagnetic particles within Daphnia resting eggs. High-field (HF) resonance lines near g=2 resulted from single superparamagnetic particles, were detected from ESR spectra of Daphnia resting eggs. The size of isolated superparamagnetic particles within Daphnia resting eggs was calculated to be approximately 13 nm in diameter by analysis of the temperature dependence of the HF line width. Small-angle X-ray scattering (SAXS) analysis of Daphnia resting eggs also showed that average size of superparamagnetic particles in diameter, equivalent to magnetite, was approximately 13 nm. The combination of FMR and SAXS measurement is very effective in estimating the size of superparamagnetic particles in biological organisms, with difficulties of preparing for samples for measurement by electron microscopy. However, Chlorella, with that Daphnia were raised, did not show FMR spectra, showing no magnetic particles within Daphnia resting eggs. Therefore, it suggested that superparamagnetic particles within Daphnia resting eggs, were mineralized in Daphnia as the result of biomineralization of Fe originated from Chlorella.

No MeSH data available.