ESR studies on collagen irradiated with protons

Chipara, Mircea; Romero, J. Reyes; Ignat, M.; Constantinescu, B.; Secu, C.E.

doi:10.1016/s0141-3910(02)00381-6

Cited by 10 publications

(8 citation statements)

References 12 publications

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“…At low microwave power, a partly resolved quintet (Q) was found show- ing hfs of about 2.02 mT. This broad spectrum was assigned to the relatively stable radical, as the wings could be observed even at 340 K. The presence of such a signal was also confi rmed by Chipara et al [10] and was attributed to radical at the end of the chain CH 2 -CH 2 • showing interaction with two  and two  protons. The signal was stronger in the sequence of spectra recorded for wet collagen and in an oxygen-free atmosphere (results not shown).…”

Section: Collagensupporting

confidence: 56%

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Radicals initiated by gamma rays in selected amino acids and collagen

et al. 2019

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Calf skin collagen and three amino acids essential for its structure, namely glycine, L-proline and 4-hydroxyl-L-proline, were irradiated with gamma rays up to a dose of 10 kGy. Conversion of radicals over time or after thermal annealing to selected temperatures was monitored by X-band electron paramagnetic resonance (EPR) spectroscopy. Some experimental spectra were compared with signals simulated based on literature data from the electron nuclear double resonance (ENDOR) studies. The following phenomena were confirmed in the tested amino acids: abstraction of hydrogen atom (glycine, proline, hydroxyproline, collagen), deamination (glycine, hydroxyproline), decarboxylation (hydroxyproline). Chain scission at glycine residues, radiation-induced decomposition of side groups and oxidative degradation were observed in irradiated collagen. The decay of radicals in collagen saturated with water occurred at lower temperatures than in macromolecules having only structural water. The paramagnetic centres were the most stable in an oxygen-free atmosphere (vacuum). Radical processes deteriorated the structure of collagen; hence, radiation sterilization of skin grafts requires careful pros and cons analysis.

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Section: Collagensupporting

confidence: 56%

“…The impact of ionizing radiation on collagen is still not fully understood. Chipara et al and Bowes et al reported that irradiation reduces molecular weight of protein due to backbone cleavage [10,11].…”

Section: Introductionmentioning

confidence: 99%

Radicals initiated by gamma rays in selected amino acids and collagen

et al. 2019

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“…Initially a fall occurs that corresponds to the destroyed, density rises as a result of the structural changes in the polymer, i.e., the formation of the double bonds and crosslinks, which bind the molecules more closely together and lead to a tighter packing of the polymer chains. 23,24 Values for % strain at break are shown in Figure 2, presenting a decreasing trend with slight variations. After 10 kGy dose rate of irradiation, % strain at break was found to decrease with the increase in radiation dose.…”

Section: Resultsmentioning

confidence: 98%

“…Melting temperature increased after electron irradiation (159. 24 C at 0 kGy, 160.5 C at 20 kGy, and 159.7 C at 40 kGy). However, at 10 and 70 KGy melting temperature decreased after electron irradiation.…”

Section: Figure 7 Tanmentioning

confidence: 95%

Effect of electron beam irradiation on mechanical and dielectric properties of polypropylene films

Pawde

Parab

2010

J of Applied Polymer Sci

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In the present investigation the effect of electron beam irradiation on the mechanical properties of thin films of Polypropylene (PP) were measured. The dielectric properties of PP films were carried out in the frequency range from 20 Hz to 1 MHz at various DC bias potential. All measurements were carried out at room temperature. It is found that the electron beam irradiation caused an increase in Young's Modulus of PP film dose of up to 70 kGy were applied, but tensile strength and % elongation at break were found to be decrease with the increasing dose rate. The significant changes were observed in the case of dielectric constant and dielectric loss for electron irradiated PP films. The DSC results indicate that irradiation on PP films changes the thermal behavior. Minor differences in FTIR spectra were observed after irradiation treatment. It is observed that, the effect of radiation damage results in improvement in mechanical strength of the films. The increased dielectric constant and dependence of the bias voltage in case of irradiated and unirradiated PP films has been reported. It is suggested that, the PP films modified with the electron beam irradiation can be used as a good dielectric material for different electronic devices.

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“…Many have investigated these processes using electron spin resonance (ESR) or EPR. These include Gasimov et al1, 2 and L'vov et al3 (fibrous proteins), Cope et al4 (hoof horn material), Alonso et al5 (stratum corneum from rats), Chandra and Symons6 (1987) and Symons et al7 (1995) (human fingernail), Shavachko et al8 (human hair), and Chipara et al9 and Gasimov et al10 (collagen irradiated with protons). EPR spectroscopy has been used to study aspects of other natural materials such as wool keratin (Mamedov,11 Smith,12 Shatkay,13 and Gogginger14) and silk fibroin (Gasimov15 and Kweon16).…”

Section: Introductionmentioning

confidence: 99%

Studies of wool keratin by EPR spectroscopy

Pielesz

2006

J of Applied Polymer Sci

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Electron paramagnetic resonance (EPR) tests were conducted on four kinds of interrelated samplesnatural undyed wool fibers (SW3, SW5), fibers dyed with model direct dyes (1W, 5W), fibers treated destructively with formic acid for descaling and dyed with the same dyes (K1W, K5W), and the dyes themselves (1%). For all samples, a radical signal of g ϭ 2.007 was detected. The presence of Mn 2ϩ and Fe 3ϩ ions in the wool fiber structure was postulated. Modifications of disulfide regions of fiber matrix were also analyzed.

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ESR studies on collagen irradiated with protons

Cited by 10 publications

References 12 publications

Radicals initiated by gamma rays in selected amino acids and collagen

Radicals initiated by gamma rays in selected amino acids and collagen

Effect of electron beam irradiation on mechanical and dielectric properties of polypropylene films

Studies of wool keratin by EPR spectroscopy

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