Effect of γ-irradiation on the occurrence of pathogenic microorganisms and nutritive value of four principal cereal grains

The effects of ⁶⁰Co γ-photon-irradiation on the natural occurrence of pathogenic microorganisms in four principal cereal grains and on amino acids and vitamins in these cereals were investigated. The total numbers of aerobic bacteria were reduced by three logarithmic decades when grains were given a dose of 10 kGy. Coliforms and “coagulase- positive” staphylococci were inhibited by a dose of 1 kGy, whereas fungi were inhibited by a dose of 5 kGy. The 15 kGy dose eliminated viable microorganisms in cereal grains, and about 10–30 colony-forming units of Clostridium sp. per gram of grain survived after this dose. The dose of 10 kGy did not cause any measurable destruction of total amino acids. Thiamin was reduced by 22–33% and riboflavin by 10–16% after a dose of 10 kGy. Irradiation did not increase the acid values significantly, but did increase the peroxide values, which was not accompanied by the off-odors of cereals. We conclude that the overall dose of 10 kGy is very effective for microbial decontamination of cereal grains, and does not adversely affect the nutritional quality of cereal grains.     

The gamma-ray response of clear polymethylmethacrylate dosimeter radix RN15®

Basic characteristics of different batches of Radix RN15® dosimeter, a commercially available undyed polymethylmethacrylate dosimeter, was studied for its application to process control of radiation sterilization. Radix has relatively small deviation of thickness, optical absorption spectrum, and optical density values before irradiation. The response curves, in terms of net optical density per unit thickness (ΔOD/mm) as a function of absorbed dose, D_PMMA, are nearly linear up to 15 kGy and become sublinear at higher doses. Scattering of dose response in 5 dosimeter replicates is ± 1% (1 σ). The dose-response slope at 25 kGy while held at irradiation temperatures in the range 0–60°C, relative to those under 25°C, increases with temperature up to 40°C, the maximum point, and decreases at higher temperatures. Over the temperature range of 10–50°C, the variation with temperature of evaluated dose derived from the calibration curve at 25°C is less than 5% when using a dose rate of 6 kGy/h. At lower dose rates (e.g. 0.7 kGy/h) the irradiation temperature dependence is negligible over this temperature range. The temperature dependence at 40 kGy is less severe than that at 25 kGy. The post-irradiation stability of dose response is less than 5% for more than 100 h after 25 kGy irradiation and storage at 0–35°C. The change in optical density of unirradiated dosimeters 3 years after manufacturing is negligible when the dosimeters are stored at controlled laboratory conditions of temperature (25°C) and relative humidity (40%). The 3-year-old dosimeters by irradiation to a dose of 25 kGy show about 2% lower response than that at 25 kGy at the beginning of the 3-year period.     

Preparation of the hypoxia imaging PET tracer [F]FAZA: reaction parameters and automation

¹⁸F-labeling of the nitroimidazole nucleoside analogue 1-(5-fluoro-5-deoxy--D-arabinofuranosyl)-2-nitroimidazole (FAZA) was developed to use this tracer in PET for detection of hypoxia. Parameters for labeling and hydrolysis were optimized with regard to amount of precursor, temperature and time. Labeling yields reached a maximum of 62±4% at 100 °C within 5 min using 5 mg of precursor. Hydrolysis was best performed with 1 mL of 0.1 N NaOH at 20 °C for 2 min. Transfer of these conditions to an automated synthesizer resulted in an overall radiochemical yield of 20.7±3.5%. Absolute yields at EOS were 9.8±2.3 GBq of [¹⁸F]FAZA ready for injection (n=21; 50 min after EOB; irradiation parameters: 35 μA, 60 min). Thus, a convenient approach suitable for large-scale production of [¹⁸F]FAZA was developed by an automated process.     

The effect of contrast temperature water therapy on repeated sprint performance

The aim of this study was to compare the effectiveness of two recovery techniques on blood lactate and repeated sprint performance. In a randomised cross-over design 20 junior representative rugby players (aged 19 ± 1 years) were given either contrast temperature water therapy or active recovery after performing a repeated sprint test. The test was then repeated 1 h later to gauge the effects of the two recovery methods on subsequent repetitive sprinting performance. One week later, the two groups were reversed and the testing repeated. The test consisted of ten 40-m sprints with a 30-s turn-around between sprints. Recovery consisted of 6 min slow jogging (6.8 km h⁻¹) for the active recovery group or 6 min of contrast temperature water therapy consisting of three 1-min hip-height immersions in cold water (8–10 °C) alternated with three 1-min hot water (38 °C) showers. Blood lactate concentration and heart rates were measured throughout the testing. Relative to the active recovery group the contrast temperature water therapy group showed a substantial decrease in blood lactate concentration 3 min after the procedure (−2.1 mmol L⁻¹, 95% confidence limits, ±1.8 mmol L⁻¹), and substantially lower heart rates both during the procedure (−9.1 ± 8.7 min⁻¹) as well as 1 h later during the second set of sprints (−11.7 ± 8.6 min⁻¹). Effects of recovery group on repeated sprint performance were small to trivial and unclear. Compared to active recovery, contrast temperature water therapy decreases blood lactate concentration and heart rate but has little effect on subsequent repetitive sprinting performance.     

Physiological and psychological responses to a 12-week BodyBalance training programme

BodyBalance is a popular mind–body program practised at numerous leisure centres throughout the western world that makes many unsubstantiated claims as to the benefits of participation. This study examines physiological and psychological responses in adults, aged (mean ± S.D.) 43.9 ± 10.9 years, to a 12-week ‘BodyBalance’ exercise program. An exercise intervention group (n = 17) undertook three 1-h classes, each week for 12 consecutive weeks while the control group (n = 17) attended three 90-min ‘health lectures’. ANCOVA demonstrated significant differences between the control and exercise groups in body mass, skinfold measures, total girth circumference from six sites, maximal isometric back strength, five measures of flexibility and state anxiety. Post-hoc tests on the experimental group data showed body fat decreased significantly by 1.10 ± 1.02% (t = 4.44; P < 0.01), girth by 4.40 ± 5.80 cm (t = 3.13; P < 0.01) and back strength increased by 17.12 ± 15.39 kgf (t = −4.59; P < 0.01). Flexibility was also significantly enhanced with performance of the modified sit-and-reach test increasing by 5.90 ± 2.56 cm (t = −9.50; P < 0.01), hip flexion by 9.84 ± 8.41° (t = −4.82; P < 0.01), hip extension by 7.65 ± 4.48° (t = −7.04; P < 0.01), hip abduction by 10.00 ± 4.91° (t = −8.40; P < 0.01) and lateral trunk flexion by 3.06 ± 5.72° (t = −2.21; P < 0.05). Finally, state-anxiety (STAI) was significantly reduced intra-class at weeks 1, 6 and 12 by 9.24 ± 9.46 (t = 4.02; P < 0.01), 6.59 ± 6.26 (t = 4.34; P < 0.01) and 7.18 ± 5.50 (t = 5.38; P < 0.01), respectively. The findings of this study suggest mind–body exercise programs like BodyBalance could significantly benefit state-anxiety as well as strength, flexibility, and anthropometry around the trunk.     

Thermoluminescence and electron spin resonance properties of some travertines from Turkey

For the sake of dating certain calcite geological samples, the TL and ESR properties of travertines from Denizli (in the southwestern part of Turkey) were studied and the effects of pre-heating temperature and pre-heating time on the sensitivity of the samples to radiation evaluated. Heat treatment above 350°C increases the sensitivity of all radiation-induced TL peaks except the 330°C glow peak. Results of gamma-ray dose calibration in travertine (CaCO₃ crystal of trigonal symmetry) indicate that the 180 and 280°C TL peak amplitudes increase exponentially with dose. We show that second-order kinetics characterizes the 180 and 280°C glow peaks reasonably well. The Mn²⁺ lines of the ESR spectra are used to investigate the thermal decomposition processes of travertine samples, showing very good agreement with those of thermogravimetry. Glow mechanisms of TL in travertine have also been studied using ESR analysis. The pre-heating and subsequent laboratory irradiation procedure is found to enhance the TL and ESR signals of CO₃³⁻ and CO₂⁻ centres. An isochronal thermal anneal sequence experiment showed that 180 and 280°C peaks in travertines are correlated with CO₃³⁻ and CO₂⁻ centres in the same way that the peak at 330°C is correlated with SO₂⁻ centres. A model for the recombination mechanism is suggested on the basis of the TL and ESR measurements.     

Synthesis and evaluation of N,N-dimethyl-2-(2-amino-5-[F]fluorophenylthio)benzylamine (5-[F]-ADAM) as a serotonin transporter imaging agent

The synthesis and evaluation of a new serotonin transporter (SERT) imaging agent, N,N-dimethyl-2-(2-amino-5-[¹⁸F]fluorophenylthio)benzylamine (5-[¹⁸F]-ADAM) is reported. Nucleophilic substitution of N,N-dimethyl-2-(2-nitro-5-bromophenylthio)benzylamine with K[¹⁸F]/Kryptofix 2.2.2 in DMSO at 125°C followed by reduction with NaBH₄–Cu(OAc)₂ in EtOH at 78°C and purification with HPLC produces the desired compound with an unoptimized yield of 5–10% in a synthesis time of 150 min from EOB. The biodistribution of 5-[¹⁸F]-ADAM in rats showed a high initial uptake and relatively rapid clearance in the brain (3.221±0.762, 0.440±0.059, 0.160±0.035 and 0.028±0.003% injected dose/organ at 2, 30, 60 and 120 min after I.V. injection, respectively) with the specific binding peaking at 1 h postinjection (hypothalamus/cerebellum and hippocampus/cerebellum were 2.97 and 3.59, respectively). The initial uptake in blood, lung, kidney and heart were also high, but it cleared rapidly. The radioactivity in the femur increased with time for 5-[¹⁸F]-ADAM indicating that in vivo defluorination may occur. Metabolism studies in rats showed that 5-[¹⁸F]-ADAM was not metabolized in rat brain, but was metabolized rapidly in the blood. Blocking experiments showed that there were significant decreases in the uptake of 5-[¹⁸F]-ADAM in the brain regions (hypothalamus, hippocampus and striatum) where SERT concentrations are high when rats were pretreated with (+)McN 5652 (2 mg/kg, 5 min prior to IV injection of 5-[¹⁸F]-ADAM). These results suggest that 5-[¹⁸F]-ADAM may be a potential new serotonin transporter PET imaging agent. However, due to its rapid wash-out from the brain, defluorination in vivo and lower uptake in the brain than 4-[¹⁸F]-ADAM, 5-[¹⁸F]-ADAM may not be as useful as 4-[¹⁸F]-ADAM as a SERT imaging agent.     

Comparing three attachment systems used to determine knee kinematics during gait

This work compared three attachment systems (AS) designed to minimize soft tissue artefacts in gait analysis measurements. The systems’ displacement for different knee flexion angles and after 50 gait cycles was investigated using an EOS^® low dose biplanar X-ray system. Eighteen subjects (six per AS) were equipped with one AS and placed in five positions. Frontal and profile views were taken for each position. The bones’ 3D model and the AS's position were obtained from stereoradiographic reconstructions. The AS's relative position to the underlying bone were computed and interpreted in the anatomical coordinate systems (CS).

The AS appeared to be stable in the frontal and sagittal plane (under 1.5° average displacement around the underlying bones) but unstable in the axial plane (over 6° average displacement). The average translation along the femoral and tibial diaphysis was 4.5 mm and 2.7 mm, respectively. Femoral system B translated significantly less along the diaphysis than the other AS. Concerning the axial rotation, system C appeared to present the most important displacement but there was no statistically significant difference. Systems A and B's rotation in the transverse plane correlated to the knee flexion angle. For the tibia, system B was more stable than systems A and C (p = 0.04). On the whole, system B appeared to be the most stable system. This study highlights the fact that no system can limit displacement in the transverse plane.     

Contrast water immersion hastens plasma lactate decrease after intense anaerobic exercise

The benefits of rapid recovery after intense exercise are widely recognised, and lactate elimination is one indicator of recovery rate. This study examined the effect of contrast (alternating hot and cold) water immersion (CWI) on the rate of plasma lactate decrease during recovery after intense anaerobic exercise. Eleven subjects on each of two occasions undertook four successive 30-s Wingate tests separated by 30-s rest periods. On each occasion, plasma lactate concentration during recovery was measured 5 min post-exercise and thereafter at 5 min intervals for 30 min. On one occasion (determined randomly), the subjects recovered passively (PR) on a recovery bed and, on the other, they alternated partial body immersion in hot (36 °C) and cold (12 °C) water baths. Plasma lactate concentrations were analysed by repeated measures analysis of variance and by fitting a linear regression model, allowing for both gender and recovery mode differences. The rate of decrease in plasma lactate concentration over the 30-min recovery period was significantly higher (p < 0.001) in CWI; 0.28(±0.02) mmol L⁻¹ min⁻¹ (CWI) compared to 0.22(±0.02) mmol L⁻¹ min⁻¹ (PR). These values do not differ significantly between males and females. Contrast water immersion is a valid method of hastening plasma lactate decrease during recovery after intense anaerobic exercise for both males and females. An approximately 1.8 mmol L⁻¹ difference between the two conditions may be expected after 30 min. With differences among elite competitors as little as 1–2%, this reduction may be of practical significance.     

A liquid-scintillation-based primary standardization of Pb

A new radioactivity solution standard of ²¹⁰Pb has been developed and will be disseminated by the National Institute of Standards and Technology (NIST) as standard reference material (SRM) 4337. This new ²¹⁰Pb solution standard is contained in a 5 mL flame-sealed borosilicate glass ampoule, consists of (5.133±0.002) g of a nominal 1 mol L⁻¹ nitric acid solution, has a density of (1.028±0.002) g mL⁻¹ at 20 °C, has carrier ion concentrations of about 11 μg Pb²⁺ and 21 μg Bi³⁺ per gram of solution, and is certified to contain a massic activity (9.037±0.22) kBq g⁻¹ as of the reference time 1200 EST, 15 June 2006. All of the uncertainties cited above correspond to standard uncertainties multiplied by a coverage factor k=2. The standardization for the ²¹⁰Pb content of the solution was based on 4πβ liquid scintillation (LS) measurements using CIEMAT/NIST ³H-standard efficiency tracing (CNET). Confirmatory determinations were also performed by high-resolution HPGe γ-ray spectrometry, by 2π spectrometry with a Si surface barrier detector of separated ²¹⁰Po, and by 4πβ(LS)–γ(NaI) anticoincidence counting.     

Effect of crystallinity and irradiation on thermal properties and specific heat capacity of LDPE & LDPE/EVA

In this paper a series of low-density polyethylene (LDPE) blends with different percentages (10%, 20%, and 30%) of EVA and sets of low-density polyethylene sheets were prepared. This set consists of four subsets, which were made under different cooling methods: fast cooling in liquid nitrogen, cooling with cassette, exposing in open air, and cooling in oven, to investigate the crystallinity effects. All of the samples were irradiated with 10MeV electron-beam in the dose range of 0-250kGy using a Rhodotron accelerator system. The variation of thermal conductivity (k) and specific heat capacity (C(p)) of all of the samples were measured. We found that, for the absorption dose less than 150kGy, k of the LDPE samples at a prescribed temperature range decreased by increasing the amount of dose, but then the change is insignificant. With increasing the crystallinity, k of the LDPE samples increased, whereas C(p) of this material is decreased. In the case of LDPE/EVA blends, for the dose less than 150kGy, C(p) (at 40°C) and k (in average) decreased, but then the change is insignificant. With increasing the amount of additive (EVA), C(p) and k increased.     

Measurement of radioactivity and radon exhalation rate in different kinds of marbles and granites

Geological materials usually contaminated with naturally occurring radioactive materials (NORM) have become a focus of great attention. These NORM under certain conditions can reach hazardous contamination levels. Some contamination levels may be sufficiently severe that precautions must be taken.

The present study deals with 60 geological samples (marble and granite) from both Egyptian and foreign locations. The studied samples were analyzed and the concentrations in Bq/kg dry weight of radioisotopes were determined by gamma-ray spectrometry using hyper-pure germanium (HPGe) detector in Bq/kg dry weight. The absorbed dose rate due to the natural radioactivity in the samples under investigation ranged from 2.45±0.07 to 64.44±1.93 nGy/h for marble and from 41.55±1.25 to 111.94±3.36 nGy/h for granite. The radium equivalent activity varied from 5.46±0.16 to 150.52±4.52 Bq/kg for marble samples and from 229.52±6.89 to 92.16±2.76 Bq/kg for granite. The representative external hazard index values for the corresponding samples are also estimated and given.

The radon exhalation rates for marble and granite samples were also calculated by using solid state nuclear track detector (CR-39). The value of radium exhalation rate varied from 8.0±2.39 to 30.20±5.06 Bq/m²/d for marble and 6.89±1.72 to 25.79±4.38 Bq/m²/d for granite and the effective radium content was found to vary from 1.700±0.51 to 6.42±1.08 Bq/kg for marble and 1.29±0.32 to 5.63±0.96 Bq/kg for granite. The values of the radon exhalation rate and effective radium content are found to correspond with the values of uranium concentration measured by the HPGe detector in the corresponding sample.     

Preparation and evaluation of [Ho] holmium-dimethyl diethylenetriaminepentaaceticacid (DMDTPA) as potential radiopharmaceutical for endovascular radiation therapy (EVRT)

Holmium-166 with its favorable radiation characteristics could be used in endovascular radionuclide therapy (EVRT) technique in liquid filled low-pressure balloon angioplasty. ¹⁶⁶Ho-dimethyl di ethylene triamine penta acetic acid (DMDTPA) was prepared and its biodistribution carried out to evaluate its suitability as an EVRT formulation. DMDTPA was synthesized, characterized and was complexed with ¹⁶⁶Ho. The complex was stable at 37°C in human serum environment and at room temperature for 48 h. Biodistribution studies in mice revealed rapid renal clearance (90% of the injected dose in 30 min p.i.) with insignificant retention in any of the major organs including bone. The studies show that ¹⁶⁶Ho-DMDTPA is a good formulation which can be explored as an EVRT source.     

Electron spin resonance age determination of a travertine sample from the southwestern part of Turkey

Travertine powdered samples collected from Denizli in the southwestern part of Turkey appear to be suitable for dating by ESR analysis due to presence of a g=2.0006 ESR signal. In general, ESR spectra of natural travertine show two absorption lines: g=2.0006 and g=2.0056. ⁶⁰Co gamma-ray irradiations enhance the g=2.0006 signal but not g=2.0056. The signal amplitude of the g=2.0056 line remains constant and shows no dose dependence after annealing at 150–180°C for periods from 15 min to 2 days. Line g=2.0056 disappears in turn after an annealing of 15 min at 400°C. Thermal annealing experiments at different temperatures for different annealing times show that the only travertine ESR signal stable enough for dating of ages over the past 10 Ma, is the one at g=2.0006. The present ESR dating result is 1.11±0.11 Ma. The g=2.0006 signal used for dating appears to correspond with the 280°C TL peak, but at elevated temperatures the mean life, accumulated dose and age of the latter is significantly less than that measured by post irradiation analysis using the ESR signal. This can be attributed to coming from other carbon-containing paramagnetic centers. In fact, gamma-ray absorbed dose rate dependence of the ESR signal has been studied, and no dependence was observed over a 12-fold change in dose rate.     

Comparative dosimetric study of two strategies of intensity-modulated radiotherapy in nasopharyngeal cancer

This study compared the target volume coverage and normal tissues sparing of simultaneous integrated boost (SIB-IMRT, 1-phase) and sequential-IMRT (2-phase) for nasopharyngeal carcinoma (NPC). Fourteen consecutive patients with newly diagnosed primary NPC were enrolled in this study. The CT images were transferred to a commercial planning system for structural delineation. The gross tumor volume (GTV) included gross nasopharyngeal tumor and involved lymph nodes of more than 1-cm diameter. The clinical target volume (CTV) modeled two regions considered to represent different risks. CTV1 encompassed the GTV with 5–10-mm margin of adjacent tissues. CTV2 encompassed ipsilateral or contralateral elective nodal regions at risk of harboring microscopic tumor. A commercial IMRT treatment planning system (Eclipse Version 7.1) was used to provide treatment planning. Seven fixed-gantry (0°, 50°, 100°, 150°, 210°, 260°, 310°) angles were designated. The 14 patients were treated with sequential-IMRT, and treatment was then replanned with an SIB strategy to compare the dosimetric difference. For the sequential strategy, the dose delivered to CTV1/CTV2 in the first course was 54 Gy (1.8 Gy × 30 Fr); while CTV1 was boosted by an additional 16.2 Gy (1.8 Gy × 9 Fr) in the second course. For SIB-IMRT, the dose prescribed to CTV1 was 69.7 Gy (2.05 Gy × 34 Fr); 56.1 Gy was given to CTV2 (1.65 Gy × 34 Fr). A statistical analysis of the dose-volume-histogram of target volumes and critical organs was performed. Paired Student’s t-test was used to compare the dosimetric differences between the two techniques. The mean dose to CTV1 was 101.7 ± 2.4% and 102.3 ± 3.1% of the prescribed dose for SIB-IMRT and sequential-IMRT, respectively. The mean CTV2 dose was 109.8 ± 4.7% of the prescribed dose for SIB-IMRT and 112.6 ± 6.0% of the prescribed dose for sequential-IMRT. The maximal dose to the spinal cord was 4489 ± 495 cGy and 3547 ± 767 cGy for SIB and sequential-IMRT (p = 0.0001), respectively. The maximal dose to brain stem was significantly higher using SIB technique (5284 ± 551 cGy) than sequential-IMRT (4834 ± 388 cGy) (p = 0.0001). The mean dose to the parotid gland and ear apparatus was significantly lower using SIB-IMRT. The mean dose to the right/left parotids was 2865 ± 320 cGy/2903 ± 429 cGy and 3567 ± 534 cGy/3476 ± 489 cGy for SIB and sequential-IMRT, respectively (p = 0.0001). Target coverage was the same for both techniques; the dose distribution in the elective nodal area with SIB was superior to that with sequential-IMRT. SIB-IMRT provides better sparing of parotid gland and inner ear structures. Extra caution should be taken when applying SIB-IMRT since critical organs close to the boost volume may receive higher doses.     

Dosimetric study of a new palladium seed

In this paper, the dosimetric parameters for a new palladium seed design: the InterSource^103, 1 are presented as recommended by the AAPM in the TG-43 formalism. Measurements are made with LiF thermoluminescent dosimeters (size of 1 mm³) in solid water phantoms WT1 to obtain the dose constant, the radial dose function and the anisotropy function. The TLD were calibrated at 6 MV and an energy correction factor of 1.40 has been applied. The same dose parameters are also obtained by Monte Carlo calculations (MCNP4B) in solid water and in liquid water. The calculated and the measured TG-43 functions for solid water are in excellent agreement. In WT1, the calculated dose rate constant is 0.657±1% and the measured value is 0.672±7%. The calculated value for water is 0.692±1%.

The comparison with the previous study (Med. Phys. 27(5) (2000)) shows a very good agreement for the dose rate constant. The agreement for the radial function is poorer. For the measurements, it can be due to the difference of TLD settings. For the calculations the discrepancy could come from the different cross-section data utilized in the different Monte Carlo codes.

In conclusion, the dosimetric functions for the new iodine seed InterSource¹⁰³ have been determined using the MCNP4B Monte Carlo code and TLD measurement in solid water WT1.     

Fading characteristics of an alanine-polystyrene dosimeter

Alanine dosimetry is useful for transfer dosimetry by long distance mailing, because of its stability. It has the advantage that the measurement of electron spin resonance (ESR) spectral signal is non-destructive to the dosimeter, with the promise that the method may supply archival dosimetry data, depending on the degree of post-irradiation stability of the signal. The effects of temperature during irradiation and storage on fading of the ESR signal were studied using an alanine dosimeter molded with polystyrene (alanine-PS dosimeter). This investigation covered a long range of storage time (up to 160 days) after irradiation to absorbed doses in the range 1 to 100 kGy, for application to transfer dosimetry between Japan and neighboring Asian countries.Dose response of an alanine-PS dosimeter depends on the temperature during irradiation. The same temperature coefficient of +0.24%/°C was measured at different dose levels of 1, 10 and 100 kGy administered at a constant dose rate of 7 kGy/h. Fading of the dose response was measured under storage at various temperatures (5–40°C). The fading curve generally has two phases with fast and slow fading rates. The response of an alanine dosimeter is relatively stable for doses of 1.4 and 14 kGy, when stored at temperatures below 25°C. However, the degree of fading was roughly 3 and 5% under a storage temperature of 40°C for 5 and 100 days, respectively, after irradiation to 14 kGy. The fading percentages at 100 kGy were 2 and 4% (after 5 days) and 6 and 15% (after 100 days) under the storage temperature of 25 and 40°C, respectively. The fading rates have a relatively small dependence on irradiation temperature. This is observed even when irradiation are made at high temperatures (60°C) and for the doses 100 kGy and above. The mechanism of decay of radicals is discussed to explain the fading characteristics of the two phases of fading. The alanine-PS dosimeter is useful for transfer standard dosimetry up to a dose level of 10 kGy when stored after irradiation at temperature below 40°C. However, consideration of temperature effects during and after irradiation is vital for accurate transfer dosimetry of high doses, especially in the southern Asian countries.     

Understanding the radiolabelling mechanism of Tc–antimony sulphide colloid

The chemistry of antimony trisulphide colloid (ATC) was examined to elucidate the radiolabelling mechanism with ^99mTcO₄⁻. Ion exchange chromatography and atomic absorption spectrophotometry techniques determined ATC to be resistant to hydrolysis in 0.1 M hydrochloric acid (HCl) at 25°C or 100°C (>97% recovery, Sb³⁺ absent). Hydrogen sulphide gas detected did not participate in the mechanism, where antimony trisulphide and ^99mTcO₄⁻ in HCl/100°C yielded 96% ^99mTc-product from a K₂S-free formulation (versus 98% when K₂S was present). ^99mTcO₄⁻ was reduced >90% by DMSA or dithiothreitol under the same conditions, identifying involvement of thiol groups. Infrared analysis of Re-ATC showed S=O bonds, indicating excess thiol groups at the colloid surface were oxidised at the expense of ^99mTcO₄⁻ reduction.     

Effects of gamma radiation on fungi infected rice (in vitro)

Abstract

Purpose: This work focuses on the effect of gamma radiation on seed born fungi (in vitro) on Oryza sativa (Swarna, Initial Evaluation Trial-5656).

Materials and methods: The responses of fungi to gamma radiation (0–4.2 kGy; 0.12 kGy/h) were studied in individual cultures of major seed-borne fungi including Alternaria alternata, Aspergillus flavus, Trichoderma viride and Curvularia geniculata.

Results: The inactivation of individual fungal-viability was noted between 1.0–2.0 kGy for A. alternata and A. flavus and 0.5–1.0 kGy for T. viride and C. geniculata. Complete inhibition was observed at <2.5 kGy. Formations of multiple germ tubes were noted in A. alternata and A. flavus at 2 kGy and 2.5 kGy, respectively. A. flavus required a higher dose to reduce viability to 10% (D₁₀) value in comparison to other selected fungi.

Conclusions: Different fungi exhibited different radiosensitivity. The dose range of 2–2.5 kGy was effective in killing all selected fungi. The fungi showing a higher D₁₀ value exhibited multiple germ tubes.     

Measuring trunk orientation with a CMOS camera: feasibility and accuracy

The purpose of this study was to develop and validate a new tool to objectively quantify trunk orientation at the bedside, especially dedicated to the measurement of the lateropulsion in acute and subacute stroke patients. We developed software to analyze 2D movement with a CMOS camera (Logitech^® Quickcam Pro 4000) and to calculate the orientation of a segment defined by two color markers. First, the accuracy, reproducibility and noise when measuring segment orientations were evaluated with the CMOS camera placed in different positions, and second trunk orientation was measured in static and in dynamic conditions both with a CMOS camera and with a gold standard 3D video system (BTS SMART-e). Results showed that the measurement was accurate (mean error = 0.05 ± 0.12°), reproducible (S.D. over five measurements = 0.005°) and steady (noise signal = 0.02°). The data obtained with the CMOS camera were highly correlated with those obtained with the 3D video system both in static and in dynamic conditions. However, the CMOS camera must be relatively well centered on the measured segment to avoid error due to image distortion. The parallax error was negligible.

In conclusion, this could be an important step in the postural assessment of acute and subacute stroke patients. The CMOS camera, a simple, portable, compact, low-cost, commercially available apparatus is the first tool to objectively quantify lateropulsion at the bedside. This method could also support the development of a rehabilitation program for trunk orientation based on biofeedback using the real-time signal provided by the device.