Effect of γ-radiation on ointment cold cream

In this paper, Co-60γ ray was used to irradiate the ointment cold cream at room temperature (25°C). We also used FTIR, GC and thin film chromatogram to analyse various irradiated samples. It was found that the ointment cold cream can be irradiated at dose of 5–35 kGy and at dose rate from 0.2 to 0.6 kGy/h at room temperature (25°C) without evident decomposition. At dose of 5–15 kGy, the number of bacteria can be reduced to hygienic standard value. The radiation sterilization is a safe method for killing the bacteria in the ointment cold cream.     

Sterilization of health care products by 5 MeV bremsstrahlung (X ray)

Radiation sensitivities of . pumilus and spores were examined to bremsstrahlung of 5 MeV EB and Cobalt -60 γ rays in order to confirm the effects of radiation and dose rate. Biological indicators (SPORTROL, NAmSA, USA) were irradiated with the X ray in the dose rate range of 4.7–47kGy/h. D-value of spores was 1.4–1.5 kGy, and that of was 1.1–1.3 kGy. The D-values of and have very small dose rate dependences to X ray, and the D-values are similar to those of γ ray. Dose distribution by X-ray and γ irradiation was measured for cartons containing 32 unit dialyzers. The D_max./D_min. of the X-ray irradiation (1.2) was smaller than that of γ ray (1.3).     

Radiation‐induced migration of additives in PVC‐based biomedical disposable devices Part 2. Surface analysis by XPS

Extruded parts of non‐sterilized and β‐irradiated (25 and 50 kGy) plasticized poly(vinyl chloride) (PVC) used for disposable medical devices have been studied to investigate the effect of sterilization on surface chemical composition. The polymer surfaces were analysed using angle‐resolved x‐ray photoelectron spectroscopy. The inner surface of the blood tubing lines showed a fairly smooth surface both before and after sterilization, so a laterally homogeneous surface can be assumed for XPS analysis. The XPS survey spectra exhibited no signals besides carbon, chlorine, oxygen and calcium. Detailed analysis of the regions showed the C 1s, Cl 2p and O 1s signals to be multi‐component, presenting signals of the PVC, the plasticizer and the other additives. Binding energies remained constant irrespective of β‐radiation dosage, but the amount of chlorine component at 198.4 ± 0.1 eV (associated with modified PVC) decreased with sterilization dosage. Angle‐resolved XPS revealed that this component is located at the outermost surface of the polymer. It can be hypothesized that the production processes themselves (extrusion and/or injection molded) already induce modifications of the polymer surface and also lead to surface segregation of the plasticizer. During the subsequent thermal sterilization of the polymer dehydrochlorination continues but, because of the very short time required by the β‐irradiation technology to sterilize devices, the atmospheric oxygen is unable to diffuse into the irradiated material, thus inhibiting further side‐degradation of the materials, such as thermo‐oxidative degradation. Copyright © 2003 John Wiley & Sons, Ltd.     

ISO radiation sterilization standards

This presentation provides an overview of the current status of the ISO radiation sterilization standards. The ISO standards are voluntary standards which detail both the validation and routine control of the sterilization process. ISO 11137 was approved in 1994 and published in 1995. When reviewing the standard you will note that less than 20% of the standard is devoted to requirements and the remainder is guidance on how to comply with the requirements.

Future standards developments in radiation sterilization are being focused on providing additional guidance. The guidance that is currently provided in informative annexes of ISO 11137 includes: device/packaging materials, dose setting methods, and dosimeters and dose measurement, currently, there are four Technical Reports being developed to provide additional guidance:

1. 1. AAMI Draft TIR, “Radiation Sterilization Material Qualification”

2. 2. ISO TR 13409-1996, “Sterilization of health care products — Radiation sterilization — Substantiation of 25 kGy as a sterilization dose for small or infrequent production batches”

3. 3. ISO Draft TR, “Sterilization of health care products — Radiation sterilization Selection of a sterilization dose for a single production batch” li]4. ISO Draft TR, “Sterilization of health care products — Radiation sterilization-Product Families, Plans for Sampling and Frequency of Dose Audits.”

     

Irradiation effects on hydrases for biomedical applications

To apply an irradiation technique to sterilize “Hybrid” biomedical materials including enzymes, we selected papain, a well-characterized plant endopeptidase as a model to examine durability of enzyme activity under the practical irradiation condition in which limited data were available for irradiation inactivation of enzymes. Dry powder and frozen aqueous solution of papain showed significant durability against ⁶⁰Co-gamma irradiation suggesting that, the commercial irradiation sterilizing method is applicable without modification. Although irradiation of unfrozen aqueous papain solution showed an unusual change of the enzymatic activity with the increasing doses, and was totally inactivated at 15 kGy, we managed to keep the residual activity more than 50% of initial activity after 30-kGy irradiation, taking such optimum conditions as increasing enzyme concentration from 10 to 100 mg/ml and purging with N₂ gas to suppress the formation of free radicals.     

Photo-luminescence of Risø B3 and PVB films for application in radiation dosimetry

Risø B3 film dosimeters (23 μm) prepared from poly(vinyl butyral) (PVB) incorporating pararosaniline cyanide, as the radiation-sensitive element and PVB films (25 μm) prepared from PVB without any additives are investigated for γ-radiation measurement using spectrofluorimetry based on their emission properties. The unirradiated Risø B3 film when excited at 554 nm shows an emission band at 602 nm while PVB film shows an emission band at 305 nm when excited at 235 nm wavelength. The fluorescence intensity of both emission bands decreases with the increase of absorbed dose due to the damage caused by ionizing radiation. The useful dose range of Risø B3 film extends up to 120 kGy while that of PVB film extends up to 60 kGy. The response of Risø B3 film increases with the increase of relative humidity during irradiation while that of PVB has less effect in the humidity range of 20–70%. The percent uncertainty associated with the measurement of the dose response was found to be ±3% (1σ) for both films. Risø B3 and PVB films show good post-irradiation stability in dark and indirect daylight where the deviation in the response overall a 2-month storage period was found to be ±5% for Risø B3 and ±2% for PVB.     

Dose response and post-irradiation characteristics of the Sunna 535-nm photo-fluorescent film dosimeter

Results of characterization studies on one of the first versions of the Sunna photo-fluorescent dosimeter™ have previously been reported, and the performance of the red fluorescence component described. This present paper describes dose response and post-irradiation characteristics of the green fluorescence component from the same dosimeter film (Sunna Model γ), which is manufactured using the injection molding technique. This production method may supply batch sizes on the order of 1 million dosimeter film elements while maintaining a signal precision (1σ) on the order of ±1% without the need to correct for variability of film thickness. The dosimeter is a 1 cm×3 cm polymeric film of 0.5-mm thickness that emits green fluorescence at intensities increasing almost linearly with dose. The data presented include dose response, post-irradiation growth, heat treatment, dosimeter aging, dose rate dependence, energy dependence, dose fractionation, variation of response within a batch, and the stability of the fluorimeter response. The results indicate that, as a routine dosimeter, the green signal provides a broad range of response at food irradiation (0.3–5 kGy), medical sterilization (5–40 kGy), and polymer cross-linking (40–250 kGy) dose levels.     

A study on feasibility of insect—control with γ-ray

Insect-control with Co-γ-ray is a method for conserving archives, books, cotton textiles, historical relics, wood structured houses and furniture, which are called irradiated objects later on. The temporary and residual effects of γ-ray on irradiated objects and the biological effects on insects are presented in this report.

Our study shows that there is no obvious harmful effect on irradiated objects when the ray is below 870 Gy, while there is obvious deterioration on the objects when the ray is above 870 Gy. On the other hand, the ray below 870 Gy is strong enough for the insects. In fact, at the dose of 43.5–130.5 Gy, the irradiated insects could be damaged on reproductive function, even sterilized, or killed.     

Surface modification of polypropylene membranes by γ-ray induced graft copolymerization and their solute permeation characteristics

Porous hydrophobic polypropylene (PP) membranes were subjected to the surface modification by the γ-ray induced graft copolymerization with hydrophilic 2-hydroxyethyl methacrylate (HEMA). The structural changes and surface morphologies of the modified PP membranes were characterized by a Fourier transform infrared spectroscopy (FT-IR), elemental analysis (EA) and field emission scanning electron microscopy (FE-SEM). Peroxides produced from γ-ray irradiation were determined by a 1,1-diphenyl-2-picryl hydrazyl (DPPH) method and the surface hydrophilicities of membranes were measured by a static contact angle measurement. The contact angle of the modified membranes reduced with the degree of grafting (DG) of HEMA onto the membrane surface, and it decreased up to about half of that before modification. The permeation behaviors of all membranes were investigated by a bovine serum albumin (BSA) filtration experiment. As a result, the DG of the modified membrane increased with the reaction time. However, in the case of irradiation dosage it showed the maximum value at 20 kGy. Also, the modified membrane showed a higher solution flux, lower BSA adsorption, and the better flux recovery after cleaning than that of the unmodified membrane. Particularly, 40.6% grafted membrane showed a two-fold increase in a BSA solution flux, 62% reduction in total fouling and three-fold increase in flux recovery after chemical cleaning.     

Study of volatile compounds from the radiosterilization of solid cephalosporins

The use of γ-rays is a promising method to sterilize thermosensitive drugs. Although radiosterilization does not modify drugs activity, this mode of sterilization produces new radiolytic products. This study is devoted to the analysis of volatile compounds which may induce a modification of odour. The volatile compounds produced by radiolysis of cefotaxime, cefuroxime and ceftazidime, three cephalosporins, were analyzed by gas chromatography with headspace sampling. They were detected and identified by mass and infrared spectrometry. An explanation of their origin is proposed.     

20 （S） -20-O- Camptothecin β-Aminopropionate： Novel Synthesis and Antitumor Activity in vitro

IntroductionCamptothecin(CPT,1, Scheme 1), a pentacyclicalkaloid isolated from theCamptotheca acuminatebyWallet al. in 1966, shows a broad-spectrum antitumoractivity[1]. However, because of its lowwater solubilityand high toxicity, its clinical applicatio…     

Comparison of γ-radiation and electron beam irradiation effects on gelatin

Gelatin is a heterogeneous mixture of water-soluble proteins of high average molecular weight derived by hydrolytic action from collagen, a protein of mammal external protective tissues. There are many characteristics of a material that can indicate its quality or performance in its intended use. The knowledge of a material's rheological characteristics is valuable to predict its pourability, its performance in a dipping or coating operation or the ease with which it may be handled, processed or used. In this work bovine powder gelatin was submitted to γ-radiation from a ⁶⁰Co source, dose rate about 7 kGy/h and to electron beam irradiation, dose rate about 11 kGy/s. The doses applied were 5, 10, 20 and 50 kGy. The radiation effects were measured following viscosity changes at 40°C of gelatin powder 10% aqueous solutions. The relationship between the decrease in viscosity of gelatin solutions and radiation dose presented close comparable values for both irradiation processes.     

The decontamination effects of gamma irradiation on the edible gelatin

The decontamination effects of gamma irradiation on the edible gelatin were studied. The results indicated that the bacterium and mold in the gelatin decreased significantly with the dose of 5 kGy treatment. However, the content of crude protein, microelement, amino acid in the gelatin remained unchanged under the irradiation of 4 and 8 kGy. The viscosity of the gelatin decreased with the increase of the irradiation dose, but the gelatin with a dose of 5 kGy treatment still accorded with the standard of the second-order class. These results suggested that the optimum irradiation dose for edible gelatin for the purpose of decontamination was in the range 3–5 kGy.     

Radiation induced decomposition of halogenated organic compounds in water

Decomposition by ionizing radiations of p-chlorophenol and tetrachloroethylene in synthetic water samples at about 2 mg Cl L⁻¹, has been studied on laboratory-scale experiments. Bicarbonate/carbonate and nitrate ions, at two concentration levels (20 and 200 mg HCO₃⁻¹ and 1 and 50 mg NO₃⁻L⁻) were added to synthetic samples in order to evaluate their influence on decomposition yield. At 5 kGy γ dose level, a quantitative degradation of p-chlorophenol is obtained whereas only qualitative consideration can be drawn on tetracholoroethylene. Comparative study with respect to degradation of p-cholophenol solutions (about 2 mg Cl L⁻¹) by γ-rays and electron beam irradiation treatment at 0.5 kGy dose level, are in progress; preliminary results indicate that irradiation with γ-rays seems to be more efficient in terms of removal efficiency respect to electron beams source.     

γ- And δ-lycorane

Hydrogenation of -anhydrodihydrocaranine (V) or anhydrocaranine (VII) with Adams catalyst in acetic acid or the Hauptmann reduction of -dihydrocaranone (XX) yielded (—)γ-lycorane (XVII). Catalytic reduction of β-anhydrodihydrocaranine (IX) with palladium-carbon in ethanol gave (+)γ-lycorane (XVIII), while with Adams catalyst in acetic acid it afforded (+)δ-lycorane (XIX) along with (—)β-lycorane (III). Reduction of anhydrocaranine in ethanol gave (±)γ-lycorane which was also obtained by hydrogenation of anhydrolycorine (X). Based on these findings, the configurational structures of -, β-, γ- and δ-lycorane were established and the configuration of dihydrolycorine was confirmed.     

Radiochemical oxidation of an ethylene-propylene-hexadiene terpolymer

The γ ray initiated oxidation of an ethylene-propylene-hexadiene terpolymer (molar ratios 87/12/1) was studied by IR spectrophotometry in the 40–90°C temperature range, with dose rates varying from 10 to 2500 Gy h⁻¹ and integrated doses up to 100 kGy. Bulk (≈8 mm) and thin (≈0.1mm) samples were studied. It appears that the oxidation is diffusion controlled in the bulk samples and non diffusion controlled in thin films. A kinetic study of IR spectral changes in these latter reveals that vinylene groups of the hexadiene monomer unit disappear in the early period of exposure, presumably by addition reactions with peroxy radicals. A very simplified mechanistic scheme allows a satisfying modelling of this process whose rate is almost proportional to the dose rate (irradiation intensity).     

Gamma irradiation effect upon positron annihilation in ultra high molecular weight poly(ethylene oxide)

Positron annihilation technique was used to reveal the evolution of small pore structure of semi-crystalline ultra high molecular weight poly(ethylene oxide) under γ-irradiation. It has been established that the structure of poly(ethylene oxide) is improved under low dose irradiation (<20 kGy), while the concentration of free-volume holes in amorphous regions increases at higher doses. The results were compared with those from small angle X-ray scattering and wide angle X-ray scattering measurements of the same samples.     

Effect of gamma radiation on growth and survival of common seed-borne fungi in India

The present work describes radiation-induced effects of major seeds like Oryza sativa Cv-2233, Oryza sativa Cv-Shankar, Cicer arietinum Cv-local and seed-borne fungi like Alternaria sp., Aspergillus sp., Trichoderma sp. and Curvularia sp. ⁶⁰Co gamma source at 25 °C emitting gamma ray at 1173 and 1332 keV energy was used for irradiation. Dose of gamma irradiation up to 3 kGy (0.12 kGy/h) was applied for exposing the seed and fungal spores. Significant depletion of the fungal population was noted with irradiation at 1–2 kGy, whereas germinating potential of the treated grain did not alter significantly. However, significant differential radiation response in delayed seed germination, colony formation of the fungal spores and their depletion of growth were noticed in a dose-dependent manner. The depletion of the fungal viability (germination) was noted within the irradiation dose range of 1–2 kGy for Alternaria sp. and Aspergillus sp., while 0.5–1 kGy for Trichoderma sp. and Curvularia sp. However, complete inhibition of all the selected fungi was observed above 2.5 kGy.     

Structural Analysis of Water-soluble Polysaccharide PIP1 Extracted from the Cultured Mycelium of Phellinus igniarius

IntroductionPhellinus igniariusbelongs to the phylum Basidio-mycota and is widely distributed in China, Japan, Aus-tralia, Philippines, and North America. The myceliumofP igniariusis perennial and grows on the stock oflatifoliate trees, such as robur, bir…     

Effect of isotacticity on radiation stability of polypropylene under lower dose irradiation

Relationship between radiation stability and isotacticity of polypropylene was studied. It was found that the higher the isotacticity, the better the radiation stability under lower dose irradiation. Special PP power with higher isotacticity can keep the melting index change less after γ-irradiation in air. Furthermore, the special PP powder with higher isotacticity has lower intention of branching after 1 kGy γ-irradiation in vacuum and has lower intention of degradation after 5 kGy γ-irradiation in vacuum.