An ESR study on biological dosimeters: Human hair

Çolak, Şeyda; Özbey, Turan

doi:10.1016/j.radmeas.2010.12.002

Cited by 14 publications

(11 citation statements)

References 27 publications

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“…Figure (a) shows an asymmetric singlet with an additional peak in a low field . The second type of ESR spectrum represents a highly asymmetric singlet with additional splitting in a HF (Fig. (b)).…”

Section: Resultsmentioning

confidence: 93%

Electron spin resonance (ESR/EPR) of free radicals observed in human red hair: a new, simple empirical method of determination of pheomelanin/eumelanin ratio in hair

Chikvaidze

Partskhaladze

Gogoladze

2014

Magnetic Reson in Chemistry

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The definition of the concentration of pheomelanin in the skin is an issue of great interest because in the case of being influenced by UV radiation, it manifests itself as a prooxidant, causing various skin disorders including melanoma that might help to explain the relatively high incidence of skin cancer among individuals with red hair. The ESR spectra of red hair samples were investigated. It was found that at low microwave power, they are characterized by two types of spectra. Red hair ESR signals result from a superposition of two spectral shapes, a singlet spectrum as a result of the existence of eumelanin and a triplet spectrum as a result of the existence of pheomelanin. At high microwave power, only triplet spectra shape was detected, caused by saturation of the eumelanin singlet. Using different concentration ratios of black to red hair, we measured ESR spectra and plotted the ratio values in each sample against a measured 'g-factor' (experimental). We found that there is a linear relationship between these two parameters. So, it is evident that using these results, the concentration ratio of pheomelanin to eumelanin in a sample of hair can be easily determined by an almost noninvasive method. This can be considered a potential advantage for many practical activities compared with other invasive methods. The concentration dependence curve of pheomelanin (µg/mg) on gexp-factor in an ESR spectrum of hair has been designed, which allows the determination of the amount of pheomelanin in hair of any color.

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Section: Resultsmentioning

confidence: 93%

Electron spin resonance (ESR/EPR) of free radicals observed in human red hair: a new, simple empirical method of determination of pheomelanin/eumelanin ratio in hair

Chikvaidze

Partskhaladze

Gogoladze

2014

Magnetic Reson in Chemistry

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“…The signal intensity of the detected EPR signal for pheomelanin and eumelanin decreased with time and followed first‐order kinetics (Figure 3). The experimentally obtained rate constants for both eu‐ and pheomelanins (0.4 to 23 × 10 −6 s −1 ) were similar to those published before for 12 kGy irradiated human hair of different shades aged in the dark, at similar temperature (21 ± 2°C) and relatively lower humidity (25 ± 3%) conditions compared to ours (4.67 to 16 × 10 −6 s −1 ; [49]) and for 50–634 Gy‐irradiated hair (1.45–4.86 × 10 −6 s −1 [39]), however, both slower than those reported for room temperature stored 1.33 kGy gamma‐irradiated (1.4 × 10 −4 s −1 [60]) or UV‐irradiated human hair (4–12 × 10 −4 s −1 [60]). The half‐life of the eumelanin‐centered radicals was 22 ± 2 day, whereas the pheomelanin‐centered radical exhibited shorter half‐lives (about 2 days).…”

Section: Discussionmentioning

confidence: 54%

Forensic determination of hair deposition time in crime scenes using electron paramagnetic resonance

Shankar

Guimarães

Napoli

et al. 2020

Journal of Forensic Sciences

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Several types of biological samples, including hair strands, are found at crime scenes. Apart from the identification of the value and the contributor of the probative evidence, it is important to prove that the time of shedding of hair belonging to a suspect or victim matches the crime window. To this end, to estimate the ex vivo aging of hair, we evaluated time-dependent changes in melanin-derived free radicals in blond, brown, and black hairs by using electron paramagnetic resonance spectroscopy (EPR). Hair strands aged under controlled conditions (humidity 40%, temperature 20-22°C, indirect light, with 12/12 hour of light/darkness cycles) showed a time-dependent decay of melanin-derived radicals. The half-life of eumelanin-derived radicals in hair under our experimental settings was estimated at 22 ± 2 days whereas that of pheomelanin was about 2 days suggesting better stabilization of unpaired electrons by eumelanin. Taken together, this study provides a reference for future forensic studies on determination of degradation of shed hair in a crime scene by following eumelanin radicals by utilizing the non-invasive, non-destructive, and highly specific EPR technique.

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“…Different colored hair contains variable amounts of melanin, but in all cases a large BG signal results. RIS signals are observed following irradiation of hair, but the significant and color-dependent BG signal due to melanin has, so far, confounded attempts to use EPR of hair as a dosimetry method (Çolak andÖzbey, 2011 andTepe Çam et al, 2014). …”

Section: Hairmentioning

confidence: 99%

Retrospective and emergency dosimetry in response to radiological incidents and nuclear mass-casualty events: A review

Bailiff

Sholom

McKeever

2016

Radiation Measurements

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Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. HIGHLIGHTSReview of the use of luminescence and electron paramagnetic resonance in retrospective and emergency dosimetry.Optically stimulated luminescence (OSL), thermoluminescence (TL) and Electron Paramagnetic Resonance (EPR) results on biological and physical materials.Descriptions of use in emergency and retrospective dosimetry, following large-scale radiological events.http://www.sciencedirect.com/science/article/pii/S1350448716302359 ABSTRACTThis paper reviews recent research on the application of the physical dosimetry techniques of electron paramagnetic resonance (EPR) and luminescence (optically stimulated luminescence, OSL, and thermoluminescence, TL) to determine radiation dose following catastrophic, large-scale radiological events. Such data are used in dose reconstruction to obtain estimates of dose due to the exposure to external sources of radiation, primarily gamma radiation, by individual members of the public and by populations. The EPR and luminescence techniques have been applied to a wide range of radiological studies, including nuclear bomb detonation (e.g., Hiroshima and Nagasaki) nuclear power plant accidents (e.g., Chernobyl), radioactive pollution (e.g., Mayak plutonium facility), and in the future could include terrorist events involving the dispersal of radioactive materials. In this review we examine the application of these techniques in 'emergency' and 'retrospective' modes of operation that are conducted on two distinct timescales. For emergency dosimetry immediate action to evaluate dose to individuals following radiation exposure is required to assess deterministic biological effects and to enable rapid medical triage. Retrospective dosimetry, on the other hand, contributes to the reconstruction of doses to populations and individuals following external exposure, and contributes to the long-term study of stochastic processes and the consequential epidemiological effects. Although internal exposure, via ingestion of radionuclides for example, can be a potentially significant contributor to dose, this review is confined to those dose components arising from exposure to external radiation, which in most studies is gamma radiation.The nascent emergency dosimetry measurement techniques aim to perform direct dose evaluations for individuals who, as members of the public, are most unlikely to be carrying a dosimeter issued for radiation monitoring purposes in the event of a radiation incident. Hence attention has focused on b...

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An ESR study on biological dosimeters: Human hair

Cited by 14 publications

References 27 publications

Electron spin resonance (ESR/EPR) of free radicals observed in human red hair: a new, simple empirical method of determination of pheomelanin/eumelanin ratio in hair

Electron spin resonance (ESR/EPR) of free radicals observed in human red hair: a new, simple empirical method of determination of pheomelanin/eumelanin ratio in hair

Forensic determination of hair deposition time in crime scenes using electron paramagnetic resonance

Retrospective and emergency dosimetry in response to radiological incidents and nuclear mass-casualty events: A review

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