The ESR signals in silk fibroin and wool keratin under both the effect of UV-irradiation and without any external effects and the formation of free radicals

Mamedov, Shaval; Aktaş, B.; Canturk, Macide; Aksakal, Baki; Alekperov, V. A.; Bülbül, Fügen; Yilgin, Resul; Rb, Aslanov

doi:10.1016/s0142-9612(02)00041-8

Cited by 33 publications

(16 citation statements)

References 3 publications

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“…Electron spin resonance is the most efficacious measuring method of free radical [14,15]. In this experiment, clean and inartificial wool was as catcher of free radicals [16].…”

Section: Double Langmuir Electron Probe and Esr Diagnosismentioning

confidence: 91%

Remote Oxygen and Nitrogen Plasma Inactivation of Staphylococcus aureus: Effects and Mechanisms

Zhang

Chen

2009

Plasma Chem Plasma Process

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The distribution of active species in remote oxygen and nitrogen plasma and the germicidal effect (GE) of Staphylococcus aureus on the surface of medical poly(tetrafluoroethylene), polyvinyl chloride and polyethylene terephthalate films, which had been widely used in medical devices, were studied. The results showed that the concentration of electrons and ions decreased rapidly with increasing the distance from the center of induction coil, which approximated to 0 at 40 cm, whereas the concentration of both oxygen and nitrogen radicals reduced slowly, which decreased 20% within 40 cm. Fast etching action on cell membrane by electrons, ions and radicals are primary reasons of oxygen and nitrogen plasma inactivation, which leads to the cellular contents effuse and engender bacteria death, however, the GE of UV radiation in remote plasma is feebleness comparatively. The GE also depends on the oxidation of gas for discharge and the surface characters of material.

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“…Electron spin resonance is the most efficacious measuring method of free radical [14,15]. In this experiment, clean and inartificial wool was as catcher of free radicals [16].…”

Section: Double Langmuir Electron Probe and Esr Diagnosismentioning

confidence: 91%

Remote Oxygen and Nitrogen Plasma Inactivation of Staphylococcus aureus: Effects and Mechanisms

Zhang

Chen

2009

Plasma Chem Plasma Process

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“…Irradiation is also used as a tool for silk fiber modification and grafting 19–22. Mamedov et al23 and Wang et al24 observed that EPR studies were also used to investigate the formation of free radicals in silk fiber after irradiation.…”

Section: Introductionmentioning

confidence: 99%

Effect of electron beam irradiation on the silk fibroin fiber/poly(ε‐caprolactone) composite

Qiao

Sun

et al. 2009

J of Applied Polymer Sci

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The effect of electron beam irradiation on silk fibroin (SF) fiber-reinforced poly(e-caprolactone) (PCL) composite was investigated by mechanical test, scanning electron microscope, dynamic mechanical thermal analysis, electron paramagnetic resonance (EPR) analysis, and Fourier transform infrared (FTIR) analysis. The results indicate that electron beam irradiation can affect the static and dynamic mechanical properties of PCL and SF/PCL composite, depending on the irradiation dose. PCL shows maximum strength and modulus at the irradiation dose of 200 kGy, and the SF/PCL composite with 45% fiber content exhibits maximum strength and modulus at the doses of 150 kGy.EPR analysis shows that during irradiation, both PCL and SF fiber can produce free radicals. Some transformations or reactions of radicals may take place between PCL and SF fiber and enhance the interfacial interaction. The microstructures of tensile fracture also show an improvement in interfacial interaction between fiber and matrix after irradiation. FTIR analysis shows that chain scissions also occur in both PCL and SF fiber during irradiation.

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“…These two types of B. mori silk yarns with close linear density were chosen to study to see whether or not they will show similar mechanical characteristics after the effect of preliminary extensions (strain history) as well as those of unstressed fibres and to provide a good statistics for the generalization of results, even though they were produced by silkworms which were grown and fed in different geographical regions that may result in the changes of mechanical characteristics. In this study, silk fibres were degummed and prepared with a similar method described earlier 9,[27][28][29][30] as follows: the cocoons were first boiled in 0.33% (w/v) soapy water for 30 min. Then, the baves were opened gently from cocoon and washed in distilled water for 1 h. These degummed fibres were then kept in ethyl alcohol for 6 h to remove any residual fatty matters and sericin completely.…”

Section: Methodsmentioning

confidence: 99%

Mechanical properties of Bombyx mori silk yarns studied with tensile testing method

Aksakal

Tsobkallo

Darvish

2009

J of Applied Polymer Sci

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The mechanical properties of Bombyx mori silk yarns and baves were investigated with tensile testing method. After silk yarns were pre-extended at different strain levels and fixed for a while followed by recovery process, the tensile characteristics were examined in detail. It was commonly observed that low preliminary extensions up to 2-3% do not cause the changes of the mechanical properties and stress-strain curves because they result in small structural changes and distortions, which were recovered within relatively short time ($ 1 min) in recovery process. However, pre-extension values >3% strain lead to great changes of the mechanical properties and fibre structure, i.e., the changes of the shape of stressstrain curve where additional transition point was observed, increase in the rigidity and stress at rupture, but decrease in extensibility as a result of orientation and destruction of the fibre structure especially in the amorphous region. It was stated that silk fibre consists of two distinct deformation regions, namely first linear region extending up to 2-3% strain and the second region beyond 2-3% strain where the main reorganization processes of the fibre structure, that is, the straining of macromolecular chains especially in the amorphous regions, the orientation of structural units such as b-sheet microcrystals in stretching direction, and the destruction of macromolecules take place.

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The ESR signals in silk fibroin and wool keratin under both the effect of UV-irradiation and without any external effects and the formation of free radicals

Cited by 33 publications

References 3 publications

Remote Oxygen and Nitrogen Plasma Inactivation of Staphylococcus aureus: Effects and Mechanisms

Remote Oxygen and Nitrogen Plasma Inactivation of Staphylococcus aureus: Effects and Mechanisms

Effect of electron beam irradiation on the silk fibroin fiber/poly(ε‐caprolactone) composite

Mechanical properties of Bombyx mori silk yarns studied with tensile testing method

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