scholarly journals Structural and Optical Investigations of Radiation Damage in Transparent PET Polymer Films

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Shiv Govind Prasad ◽  
Abhijit De ◽  
Udayan De
Keyword(s):  
Free Radicals ◽  
Gamma Irradiation ◽  
Polymer Films ◽  
Wavelength Region ◽  
Xrd Analysis ◽  
High Dose ◽  
Plane Vibration ◽  
Bending Mode ◽  
Vis Spectroscopy ◽  
Gamma Irradiated

Effects of gamma irradiation at different doses up to 135 kGy on polyethylene terephthalate (PET) polymer films have been investigated by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and ultraviolet-visible (UV-VIS) spectroscopy. From XRD analysis, it was found that even at a high dose of gamma irradiation of 135 kGy, crystallinity of the PET samples remain unchanged. However, the FTIR peak at 871 cm−1 (depicting C–H bending mode of out-of-plane vibration) and another at 1303 cm−1 (representing C–H bending mode of in-plane vibration) disappear for gamma-irradiated PET. In this study, it has also been found that γ-irradiation in air enhances the optical absorption in the wavelength region 320–370 nm. This has been attributed to free radicals being produced in the polymer by the γ-radiation. Further, the free radicals react with oxygen of air to form carbonyl group and hydroxyls. With increasing γ-dose, there is a red shift of the UV—near visible cutoff for PET. XRD and FTIR observations on γ-damage have been correlated.

Improving photoluminescence, optical and electrical characteristics of PMMA films with gamma irradiation

2021 ◽  
Author(s):  
M.F. Zaki ◽  
Nasser Shubayr ◽  
Reda M Radwan ◽  
Yazeed Alashban
Keyword(s):  
Gamma Irradiation ◽  
Polymeric Materials ◽  
Advanced Materials ◽  
Strong Impact ◽  
Electrical Characteristics ◽  
Electrical Measurements ◽  
Indirect Transition ◽  
Dielectric Parameters ◽  
Vis Spectroscopy ◽  
Gamma Irradiated

Abstract Polymeric materials are macromolecules, essentially a combination of numerous repeated subunits. Polymers are innovative and advanced materials that currently have a strong impact on our daily lives. In recent years, polymer use has been prominent due to the materials’ distinctive properties; thus, they entered different fields of science, technology and industrial-biomedical applications.The improvement of photoluminescence, optical and electrical characteristics of non-conducting Poly(methyl methacrylate) (PMMA) films was studied. Upon gamma irradiation of various doses, the photophysical and electrical properties of PMMA films were investigated using photoluminescence spectroscopy, ultraviolet–visible (UV-Vis) spectroscopy and the LCR Meter Bridge Circuit technique. The fluorescent response improved the photoluminescence (PL) spectral emission peaks according to gamma values. Strong fluorescence peaks appeared with the highest gamma dose. The UV–Vis results revealed a significant red-shift in the absorption edge as gamma doses increased. This shift exhibits a continuous decrease in the energy band gap values (from 3.50 to 2.60 eV for direct transition and from 3.05 to 1.55 eV for indirect transition). This was due to the formation of carbon clusters, which led to an increase in the electrical conductivity and improved the dielectric parameters of the irradiated PMMA films. Among a variety of measurements presented and discussed in the present study, the electrical measurements showed improved electrical characteristics of gamma-irradiated PMMA films.

scholarly journals Effect of gamma-irradiation on the properties of aluminum dihydrogen triphosphate

2017 ◽  
Vol 82 (10) ◽  
pp. 1111-1121 ◽  
Author(s):  
Weiqiang Song ◽  
Qinghuan Song ◽  
Longchao Wu ◽  
Lantao Yang
Keyword(s):  
Thermal Analysis ◽  
Corrosion Resistance ◽  
Gamma Irradiation ◽  
Electrochemical Impedance ◽  
Dose Range ◽  
Xrd Analysis ◽  
High Dose ◽  
Crystal Transition ◽  
Steel Panels ◽  
High Doses

The effect of gamma irradiation on the properties of aluminum dihydrogen triphosphate (ADTP) in the dose range of 0 to 150 kGy was studied by X-ray diffraction (XRD) analysis, thermal analysis, acid?base titration, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). Although the XRD and SEM results indicated that there were no significant effects on the crystal structure and the surface morphology of ADTP, thermal analysis revealed that the crystal transition of Al(PO3)3 from Type-B to Type-A did not occur at a high temperature in irradiated ADTP. EIS results showed that high-dose gamma irradiation (100 kGy and 150 kGy, 60Co) improved the corrosion inhibition ability of ADTP on tinplate steel. SEM was used to investigate the surface of tinplate steel panels after immersion in ADTP extracts for 69 h, and revealed that many slices were formed on the surface. The slices were attributed to the formation of Fe2P3O10. Inter-slice gaps may be the reason for the lower corrosion resistance of ADTP compared with the resistance of some toxic pigments containing lead and chromium. Overall, high doses of gamma irradiation improved the corrosion resistance of ADTP.

309 DIFFERENCES IN PRONUCLEUS FORMATION RATES BETWEEN BULLS IN RESPONSE TO GAMMA IRRADIATION OF FROZEN - THAWED SEMEN

2007 ◽  
Vol 19 (1) ◽  
pp. 270
Author(s):  
M. M. Petersen ◽  
G. B. Boe-Hansen ◽  
A. Birck ◽  
B. Avery ◽  
M. Jensen ◽  
...  
Keyword(s):  
Dna Damage ◽  
Gamma Irradiation ◽  
Sperm Quality ◽  
Membrane Integrity ◽  
Fertilization Rate ◽  
High Dose ◽  
Exact Test ◽  
Bovine Spermatozoa ◽  
Gamma Irradiated

Gamma irradiation induces DNA damage to mature bovine spermatozoa but does not affect motility, membrane integrity, or function (Fatehi et al. 2006 J. Androl. 27, 176–188), making it a useful model to evaluate the effect of fertilization with DNA-damaged spermatozoa. The objective of the present study was to analyze the fertilizing capacity of frozen–thawed gamma-irradiated sperm from 2 bulls: a bull with a high sperm quality and fertilization rate (bull A), and a bull with a low sperm quality and fertilization rate (bull B). To ensure that DNA damage was induced, frozen–thawed semen was exposed to a high dose of irradiation (90 Gy). Cumulus–oocyte complexes were obtained from abattoir ovaries and were in vitro-matured (IVM) using standard procedures (23 h in DMEM with 5% serum and eCG/hCG). For each treatment group, 3 to 5 straws of semen from the same ejaculate were used. After thawing, semen from the 2 bulls was either irradiated or held at room temperature before 1:1 dilution in sperm-TALP. During irradiation, semen was kept in the straws. The irradiated and nonirradiated sperm were used for IVF (23 h in IVF-TALP) within 1 h of thawing. IVM and IVF were carried out at 38.5�C in 5% CO2 in air. After IVF, presumptive zygotes were whole mount-fixed and 24 h later were stained with 1% aceto-orcein followed by determination of fertilization status. Fertilization was considered normal if 2 pronuclei (PN) were present. A total of 4 replicates were performed and 286 zygotes analyzed. No difference was detected between replicates, and the results were pooled. Fisher's exact test was used to determine effect of treatment. More zygotes had 2 PN after fertilization with semen from bull A (47/67 = 70%), compared with that from bull B (16/71 = 23%; P < 0.0001) using nonirradiated sperm. Irradiation of sperm significantly increased the fraction of zygotes with 2 PN from bull A (61/70 = 87%; P = 0.03), but decreased the 2 PN fractions in zygotes fertilized with sperm from bull B (2/75 = 3%; P = 0.0002). Ideally, to avoid straw variation, semen should have been pooled and divided into groups before irradiation. The variation between straws might explain the higher fertilization rates in bull A using irradiated sperm compared with nonirradiated sperm. In conclusion, there appear to be differences in fertilizing ability between bulls after irradiation of frozen–thawed sperm. This could be due to suboptimal DNA packaging, which made sperm from bull B more susceptible to radiation-induced damage. The potential irradiation-induced increase in DNA fragmentation in sperm from bull B compared with that from bull A might delay or prevent the formation of the 2 PN. Further studies are needed to investigate differences in fertilization and early embryonic development using sperm with intact or damaged DNA.

scholarly journals Graphene scavenges free radicals to synergistically enhance structural properties in a gamma-irradiated polyethylene composite through enhanced interfacial interactions

2015 ◽  
Vol 17 (35) ◽  
pp. 22900-22910 ◽  
Author(s):  
Elayaraja Kolanthai ◽  
Suryasarathi Bose ◽  
K. S. Bhagyashree ◽  
S. V. Bhat ◽  
K. Asokan ◽  
...  
Keyword(s):  
Free Radicals ◽  
Gamma Irradiation ◽  
Structural Properties ◽  
Interfacial Interactions ◽  
Polyethylene Composite ◽  
Gamma Irradiated

A unique strategy for scavenging free radicals in situ on exposure to gamma irradiation in polyethylene (PE) nanocomposites is presented.

Employing Gamma Ray Irradiated Giardia lamblia as Trialed Vaccine in Experimental Animal

2019 ◽  
Vol 9 (02) ◽  
Author(s):  
Amal Kamil Abdul Sada ◽  
Amany Mohamed Al-Kaysi
Keyword(s):  
Giardia Lamblia ◽  
Gamma Ray ◽  
Age Groups ◽  
Active Phase ◽  
Study Groups ◽  
Negative Control ◽  
Control Group ◽  
High Dose ◽  
Histopathological Changes ◽  
Gamma Irradiated

This is an experimental trial to prepare a vaccine from gamma-irradiated Giardia lamblia which is evaluated in experimental animals. The study was conducted from December 2015 to April 2016. The field survey of the parasite was conducted from those patients attending the laboratories of the Alawi Children's Hospital in Rusafa and the Al-Yarmouk Teaching Hospital in Karkh, through which 1250 stool samples of different age groups were examined. Five groups of mice were used in the study; the first was injected with normal saline and considered as a negative control group, the second was injected with cystic form of non-irradiated Giardia lamblia and considered as a positive control group, whereas the other three groups were injected with gamma irradiated Giardia lamblia at three different doses 10, 15 and 25 rad respectively. Giardia lamblia was primarily cultivated in liver infusion agar for ten days to obtain the active phase. On the sixth day, the cystic phase was purified and standardized to be used in the infection of mice with or without the exposure of gamma rays. Mice showed high sensitivity to parasitic infestation, in the gamma non-irradiated and the irradiated with gamma 10 rad, and 15 rad irradiated groups which was 100%. The results expressed an excystation process of the depleted phases and the release of the feeder phases. The results of the three irradiated groups consisted of histopathological changes of the small, and the rectum by dissection after two weeks of infection, with intestine amputation lesions, as well as ulceration and inflammation of the inflammatory cells represented in small numbers of neutrophil, lymphocytes, and eosinophils. The presence of ulceration and fall of epithelial cells in the intestinal cavity has been shown, and different forms of the parasite have been observed. Mice which was injected with irradiated G lamblia at high dose (25 rad), not show and sensitivity to the challenge infection and no excystation of thy parasite had been done. After 2 wreaks, a comparison was achieved between all study groups in which no histopathological changes were noticed in the mice irradiated with dose of25 rad. After another two weeks, a challenge dose was given (un-attenuated G lamblia) and mice were dissected after another two weeks, no changes on the level of histopathology of intestinal tissue were noticed the results suggested that mice acquire an immunity against the parasite infection.

Effect of gamma radiation on the structural, thermal and optical properties of PMMA/Sn0.75Fe0.25S2 nanocomposite

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Ali A. Alhazime ◽  
Nesreen T. El-Shamy ◽  
Kaoutar Benthami ◽  
Mai ME. Barakat ◽  
Samir A. Nouh
Keyword(s):  
Thermal Stability ◽  
Optical Properties ◽  
Gamma Irradiation ◽  
Optical Band Gap ◽  
Color Variation ◽  
Nanocomposite Films ◽  
Color Changes ◽  
Gamma Irradiated ◽  
Intermolecular Crosslinking ◽  
Amorphous Part

AbstractNanocomposite films of polymethylmethacrylate PMMA with Sn0.75Fe0.25S2 nanoparticles (NPs) were fabricated by both thermolysis and casting techniques. Changes in PMMA/Sn0.75Fe0.25S2 nanocomposite (NCP) due to gamma irradiation have been measured. XRD results indicate that the gamma doses of 10–80 kGy cause intermolecular crosslinking that reduces the ordered portion in the NPs. Bonding between the NPs and the host PMMA was confirmed by FTIR. TGA results indicate an enhancement in thermal stability in the NCP films irradiated with doses 20–80 kGy. The optical band gap was reduced from 3.23 to 2.47 eV upon gamma irradiation up to 80 kGy due bonding between the NPs and PMMA which enhanced the amorphous part of the NPs. Finally, the color variation between the blank and irradiated films (ΔE) was determined. Color changes immensely when the PMMA/Sn0.75Fe0.25S2 NCP films are gamma irradiated. Values of ΔE were as much as 31.6 which is an acceptable match in commercial reproduction on printing presses.

scholarly journals Facile Synthesis of L-Cysteine Functionalized Graphene Quantum Dots as a Bioimaging and Photosensitive Agent

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1879
Author(s):  
Mila Milenković ◽  
Aleksandra Mišović ◽  
Dragana Jovanović ◽  
Ana Popović Bijelić ◽  
Gabriele Ciasca ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Gamma Irradiation ◽  
Hela Cells ◽  
Graphene Quantum Dots ◽  
Morphological Properties ◽  
Paramagnetic Resonance ◽  
Chemical Reagents ◽  
Amino Amide ◽  
Gamma Irradiated ◽  
Electron Paramagnetic

Nowadays, a larger number of aggressive and corrosive chemical reagents as well as toxic solvents are used to achieve structural modification and cleaning of the final products. These lead to the production of residual, waste chemicals, which are often reactive, cancerogenic, and toxic to the environment. This study shows a new approach to the modification of graphene quantum dots (GQDs) using gamma irradiation where the usage of reagents was avoided. We achieved the incorporation of S and N atoms in the GQD structure by selecting an aqueous solution of L-cysteine as an irradiation medium. GQDs were exposed to gamma-irradiation at doses of 25, 50 and 200 kGy. After irradiation, the optical, structural, and morphological properties, as well as the possibility of their use as an agent in bioimaging and photodynamic therapy, were studied. We measured an enhanced quantum yield of photoluminescence with the highest dose of 25 kGy (21.60%). Both S- and N-functional groups were detected in all gamma-irradiated GQDs: amino, amide, thiol, and thione. Spin trap electron paramagnetic resonance showed that GQDs irradiated with 25 kGy can generate singlet oxygen upon illumination. Bioimaging on HeLa cells showed the best visibility for cells treated with GQDs irradiated with 25 kGy, while cytotoxicity was not detected after treatment of HeLa cells with gamma-irradiated GQDs.

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