Probability of cell transformation effect per mSv induced by α-particle radiation

Radiation carcinogenesis is one of the major biological effects considered to be important in risk assessment of radioactive exposures. The purpose of this work is to calculate the probability of cell transformation effect per mSv induced by α-particle radiation, from radon progeny, on sensitive cells of human lung. Probability was calculated by applying the analytical model cylindrical bifurcation (Jovanovi? et al., J Radioanal Nucl Chem 290(3):607–613, 2011) which was created to simulate the geometry of human airways with the geometric distribution of cell nuclei in the airway wall of the tracheobronchial tree. Cell transformation can change form or structure DNA, and this change cause that a normal cell undergoes as it becomes malignant. It is possible that radon is the number one cause of lung cancer among people who do not smoke. This analytical model of the human traheobronchial tree represent the extension of the ICRP66 (ICRP Human Respiratory Tract Model for Radiological Protection, 1994) model. Propagation of α-particle was simulated by Monte Carlo method. Reported probabilities are calculated for various targets and alpha particle energies. The sources included fast and slow mucus in BB and bb region. The targets are basal and secretory cells in BB region, and secretory cells in bb region. Results obtained in this work are unique.     

Ecological study of the migration of eel by synchrotron radiation induced X–ray fluorescence imaging of otoliths

Synchrotron radiation–induced X–ray fluorescence imaging is suitable for determining the distribution of trace elements in fish otoliths. The Sr/Ca ratio in an otolith is an indicator of salinity changes and can be used to clarify the migration history of the eel, a catadromous fish. The otoliths of eel collected from the Tone and Elbe rivers exhibited a typical catadromous pattern, i.e. birth and breeding occurred in the ocean, but the remainder of their lives was spent in fresh water. In contrast, eels from the East China Sea and North Sea exhibited an unusual sea–locking phenomenon, as they appear to have remained in marine habitats throughout their lives.     

In vitro DNA damage characterisation studies on plasmid pBR322 after exposure to γ radiation by <Superscript>60</Superscript>Co

When a biological system is either accidentally or intentionally exposed to radiation, the energy absorbed triggers a number of successive events including damage to living tissues. Major radiation damage is due to the aqueous free radicals generated by the radiolysis of water. These free radicals act as molecular marauders and in turn damage DNA, mitochondrial membrane, lipid, cellular protein, resulting in cellular dysfunction and mortality. In view of the above mentioned facts an experiment was conducted to study the genotoxic effects of γ radiation and its dose effectiveness. The present experiment was conducted on samples of plasmid pBR322 DNA as the in vitro experimental model devoid of any DNA repair and replication machinery. The samples were exposed to different doses of gamma radiations from 1 to 200 Gy. Exposure of plasmid pBR322 DNA to γ radiation resulted in production of single strand breaks as a result of which, the supercoiled (SC) form was converted to relaxed form (RL). Exposure of radiation, even at very low dose of 1 Gy, exhibited a significant damage to DNA resulting in about 70% SC form and 30% RL form of DNA. At a dose of 10 Gy the SC form was reduced to about 37% and further 5% at a dose of 50 Gy with about 88.5 and 6.5% RL and linear (L) forms of DNA respectively. Thus, the disappearance of supercoiled form of plasmid pBR322 DNA was found to be directly related to radiation dose and exhibited a radiation dose dependent pattern.     

Study of C60·2S8 by the methods of induced electron emission

It was shown by the methods of induced electron emission that a transfer of the electron density from C₆₀ molecules to the eight-membered ring of sulfur is characteristic of C₆₀·2S₈. The value of the (+)-plasmon energy for C₆₀·2S₈ is approximately 1 eV less than that for pure C₆₀. In a high vacuum, the C₆₀·2₈ surface is depleted in sulfur.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2149–2152, December, 1994.     

Macroscopic lamellae orientations of diblock copolymer induced by dynamic shear

Computer simulation based on the coupled map lattices has been carried out for morphologies of the diblock copolymeric system under applied periodic shear deformation.The main effort is concentrated on the influence of pre-annenling history on the lamellae orientations in dynamically sheared diblock copolymers.It is found that whatever the quenching temperature is,the perpendicular orientation (i.e.the lamellae normal is parallel to the vorticity axis) is always observed if the dynamic shear deformation with shear amplitude F=1.0 and reduced shear frequency=0.005 is applied during annealing.In contrast to that,the parallel orientation (i.e.the lamellae normal is parallel to the velocity gradient direction) is observed if the dynamic shear with the same amplitude and frequency is applied to a thoroughly annealed (with the annealing time t>4 000) diblock copolymer.Therefore,it is pointed out that the selection of lamellar orientations in dynamically sheared diblock copolymers is not solely dependent on th     

Modification of polyethylene films by radiation grafting of glycidyl methacrylate and immobilization of β-cyclodextrin

Glycidyl methacrylate was grafted onto polyethylene films using a preirradiation method with γ rays. The effect of absorbed dose, monomer concentration, and reaction time on the degree of grafting was determined. The grafted samples were verified by FTIR-ATR spectroscopy. β-Cyclodextrin was immobilized onto polypropylene modified with glycidyl methacrylate, and the ability of the cavities of β-cyclodextrin to form inclusion complexes was demonstrated using the typically organic compound approach with m-toluic acid (3-MBA) as a probe.     

SDS-PAGE study on photooxidation damage of lysozyme induced by riboflavin

The photooxidation damage of lysozyme under 315-375 nm irradiation in the presence of riboflavin was studied by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE).Indica- tions showed that the mechanisms and products of oxidative damage were relative to the concentra- tion of riboflavin,the time of irradiation and the ambience.The type I process was examined in a nitrogen saturated solution,whereas both type I and type II were observed in an aerobic atmosphere and type II was the dominant process.The study also suggested that antioxidants,such as melatonin, can reduce the damage of lysozyme effectively.     

PP films grafted with N-isopropylacrylamide and N-(3-aminopropyl) methacrylamide by γ radiation: synthesis and characterization

Simultaneous grafting of N-isopropylacrylamide (NIPAAm) and N-(3-aminopropyl) methacrylamide hydrochloride (APMA) on polypropylene (PP) was investigated for obtaining interfaces that are stimuli-responsive under physiological conditions. A pre-irradiation method was optimized tuning the γ-irradiation dose, reaction time, temperature, and monomers concentrations. FT-IR ATR and XPS analysis of the grafted copolymers evidenced a greater content in NIPAAm than in APMA; the APMA/NIPAAm ratio increasing with the concentration of APMA in the reaction medium and when the grafting was carried out in 1 M NaNO₃. The grafted films were characterized regarding their thermal properties (DSC and TGA) swelling behavior and contact angle. Immersion of the pre-irradiated films in 1 M NIPAAm/0.5 M APMA aqueous solution rendered PP-g-(1NIPAAm-r-0.5APMA) which exhibited rapid and reversible transitions showing a LCST around the physiological temperature. By contrast, a greater content in APMA enhanced the hydrophilicity and prevented the shrinking of PP-g-(1NIPAAm-r-1APMA).     

Synthesis of Fluorinated Polyurethane/Polyacrylate Hybrid Emulsion Initiated by 60Co γ-Ray and Properties of the Latex Film

Based on the solvent-free method, novel fluorinated polyurethane/polyacrylate hybrid emulsions, dodecafluoroheptyl methacrylate (DFMA) as fluorinated monomer, were successfully prepared via emulsion polymerization without traditional emulsifier. For the purpose of increasing the grafting ratio of polyurethane and polyacrylate, ⁶⁰Co γ-ray radiation polymerization had been adopted to enhance the hardness of latex film. The chain structure and polymerization progress were confirmed by the analysis of Fourier transform infrared spectroscopy. The grafting ratio of polymethyl methacrylate and polyurethane was obtained by calculating the ratio of N–H peak integral area and Ph(C=C) peak integral area. The effect of DFMA content on thermal stability, mechanical property and water resistance were investigated systematically by thermal weight loss analysis, tensile strength test, absorbed water ratio and water contact angle.     

Reaction mechanism of hydroxymaleimide induced by γ-irradiation in alcohol solvents

Methanol and 2-propanol solutions of hydroxymaleimide were irradiated with γ-ray and mechanism of its γ-irradiation-induced reactions was investigated through final-product analyses using high performance liquid chromatography (HPLC) coupled with mass spectroscopy. An addition reaction of a solvent radical toward hydroxymaleimide was dominant among its oxygen-free γ-irradiation-induced reactions in its alcohol solutions while it is known that electron attachment toward hydroxyphthalimide or hydroxysuccinimide is dominant among their γ-irradiation-induced reactions. The radical adduct abstracts hydrogen from solvent molecule to re-produce a solvent radical. Therefore, the degradation efficiency of hydroxymaleimide was more than ten times larger than that of hydroxyphthalimide and hydroxysuccinimide. Dimer was also produced through electron attachment process in the solutions of hydroxymaleimide. In addition, it was found that the degradation efficiency increased with decrease in dose rate. An additional reaction of a solvent radical toward hydroxymaleimide competes with a radical–radical recombination. The latter was reduced, with the former leading to efficient degradation of hydroxymaleimide increased by irradiation at lower dose rate. On the contrary, the production yield of the adduct radical as well as the degradation efficiency of hydroxymaleimide was inhibited in the presence of oxygen.     

Deuteron dynamics in the γ phase of titanium deuterides as probed by NMR

Titanium deuterides TiD _x (x = 1.92, 1.98, 2.0) and the Ti_0.95Zr_0.05D_1.76 alloy were studied by ²H NMR in magnetic fields of 4.69 and 7.04 T in the temperature range 120–500 K. The correlation coefficients of deuteron self-diffusion calculated from the temperature dependence of the line width were described by the Arrhenius equation. The activation energies E _a and preexponential factors were determined. For the Ti_0.95Zr_0.05D_1.76 alloy, the line width was found to depend on the magnetic field, which was explained by the fact that deuterons are in different environments formed by titanium and zirconium atoms.     

Analysis of diterpenoid compounds from the latex of two Euphorbiaceae by liquid chromatography‒electrospray ionisation mass spectrometry

The latex of Euphorbia papillosa A.St.-Hil. and Sapium glandulosum (L.) Morong was phytochemically investigated by liquid chromatography/mass spectrometry. The results reveal the presence of tigliane-type diterpenoid compounds, particularly 12-deoxyphorbol esters, in both species. In addition, ingenane-type diterpene esters were found in the latex of E. papillosa. The latex of S. glandulosum showed only tigliane-type diterpenes, confirming the literature data on this genus. According to mass data, we are proposing the presence of 10 compounds derived from 12-deoxyphorbol monoesters and diesters, from one 12-deoxyphorbaldehyde, from two ingenol derivatives and from one nitrogen-containing phorbol ester in the latex of the analysed species. Considering that 12-deoxy tigliane diterpenes are described as antitumour and antiviral agents, these results indicate a pharmacological potential for these two Euphorbiaceae species.     

Investigation of the effect of 60Co-γ radiation on single and polycrystalline polyethylene by broad line N.M.R.

The broad line N.M.R. spectra of irradiated and unirradiated high density bulk (HD) and single crystals (SC) of polyethylene were found to give rise to two components, e.g. broad and narrow lines, attributed to crystalline and amorphous regions, respectively. An increase in the line width of the narrow component with radiation dose is more marked in bulk HD specimens, and is ascribed to crosslinking in the radiation-sensitive amorphous region; whereas no such increase is apparent for the SC specimen. Though there seems to be a slight increase in the second moment of the total absorption curve with radiation up to about 200 Mrad, both the second moment and the line width of the broad component was found to decrease with radiation dose for both the samples. This indicates an increased chain mobility in the crystalline regions and is considered to be due to the destruction of regularity in the crystal lattices by the combined processes of crosslinking (or endlinking) in the amorphous regions and the formation of lattice defects and imperfections by the ionizing radiation. A relatively faster decrease of line width with radiation dose above about 1000 Mrad may be attributed to the predominance of the latter process at high doses.     

Synchrotron radiation induced photoionization and photodissociation of carbon monoxide in the 14–35 eV region

Carbon monoxide has been excited with monochromatic synchrotron radiation in the 14–35 eV range using the Swedish synchrotron facility MAX in Lund. The decay products were studied in various detection channels such as formed CO⁺ and C⁺ ions using mass spectroscopy and visible or VUV fluorescence using photon detection. A rich line structure is observed which is attributed to CO Rydberg series converging to theX,A,B,D,C andE states in CO⁺. While a great number of these lines are already known, some of them are classified here for the first time. The combination of information from the fluorescence spectra and the mass spectra contribute important information concerning the autoionization and predissociation of these various Rydberg series.     

Rheological study of physical cross-linked quaternized cellulose hydrogels induced by β-glycerophosphate

As a weak base, β-glycerophosphate (β-GP) was used to spontaneously initiate gelation of quaternized cellulose (QC) solutions at body temperature. The QC/β-GP solutions are flowable below or at room temperature but gel rapidly under physiological conditions. In order to clarify the sol-gel transition process of the QC/β-GP systems, the complex was investigated by dynamic viscoelastic measurements. The shear storage modulus (G') and loss modulus (G″) as a function of (1) concentration of β-GP (c(β-GP)), (2) concentration of QC (c(QC)), (3) degree of substitution (DS; i.e., the average number of substituted hydroxyl groups in the anhydroglucose unit) of QC, (4) viscosity-average molecular weight (M(η)) of QC, and (5) solvent medium were studied by the oscillatory rheology. The sol-gel transition temperature of QC/β-GP solutions decreased with an increase of c(QC) and c(β-GP), the M(η) of QC, and a decrease of the DS of QC and pH of the solvent. The sol-gel transition temperature and time could be easily controlled by adjusting the concentrations of QC and β-GP, M(η) and DS of QC, and the solvent medium. Gels formed after heating were irreversible; i.e., after cooling to lower temperature they could not be dissolved to become liquid again. The aggregation and entanglement of QC chains, electrostatic interaction, and hydrogen bonding between QC and β-GP were the main factors responsible for the irreversible sol-gel transition behavior of QC/β-GP systems.     

Novel carboncarbon bond formation induced by depalladation of organometallic compounds

Two internal alkynes undergo insertion at 20°C into the PdC bond of the cyclopalladated derivative of dimethylaminomethylferrocene to give new organometallic compounds. When the reaction with diphenylacetylene is performed at higher temperatures, depalladation occurs readily to give six- and seven-membered ortho-fused rings through new annulation reactions of phenyl groups, formation of one of these involving also the cleavage of a CN bond.     

Stabilization of the γ form of the rare earth sesquisulfides at lower temperature by doping with Calcium

The preparation of several samples forming a solid solution that can be formulated as Ca_(3/2)yR_2−y_{0.25−(1/2)y}S₃ (R = Ce, Sm, Gd) (0 ≤ y ≤ 0.30) is reported, together with their structural characterization, mainly through transmission electron microscopy. The introduction of Ca²⁺ into the rare earth metal sesquisulfide matrix stabilizes the γ form phase at 900 °C. This effect can be related to the non-stoichiometric nature of this phase, R_3−x_xS₄, because the introduction of Ca²⁺ requires the elimination of cation vacancies from the structure: 2R³⁺ + → 3Ca²⁺ (R = rare earth metal;  = cation vacancies). However, a NaCl-type solid solution is formed for R = Eu, formulated as Eu_1−yCa_yS. Well-ordered crystals are found in every sample, as it is revealed by transmission electron microscopy images and diffraction patterns. The color properties of the samples have been evaluated with reflectance spectra in the visible range and with L*–a*–b* coordinates.     

Alignment of liquid crystals induced by a photopolymerized self‐assembled film

An alignment film derived from a photopolymerized self‐assembled film may be used to orient nematic liquid crystals after irradiating the film with linearly polarized UV (LPUV). A photosensitive cationic amphiphile was first synthesized containing two double bonds and which could be polymerized by UV. A layer‐by‐layer self‐assembled multilayer film was next prepared in an aqueous solution of the cationic amphiphile and poly(sodium 4‐styrenesulphonate); the UV‐Vis spectra showed that each layer of the LBL multilayer film was uniform. When the film was irradiated by LPUV, the photosensitive double bonds underwent [2+2] cycloaddition along the vector direction of LPUV. The polarized UV‐Vis absorption spectra also provided evidence that the film was anisotropic, i.e. the photopolymerization was along a certain direction. The anisotropic film was used as an alignment layer for nematic liquid crystals, and observations under a polarizing microscope indicated that the alignment of the liquid crystals was good, as expected, and that the orientation direction of the liquid crystals was always perpendicular to the electric vector of the irradiating LPUV.     

Small-angle scattering of synchrotron radiation investigations of nanostructured alumina membranes synthesized by sol–gel method

Alumina asymmetric ceramic membranes were prepared by sol–gel method. Research on structure of alumina membrane active layer is conducted by methods of physical nitrogen adsorption and small-angle scattering of synchrotron radiation, the obtained data confirms and supplements each other. Surface area for the studied material varies from 255 to 264 m²/g, average pore diameter varies from 5.3 nm to 5.4 nm.