Irradiation Apparatus Research Articles

Ability of high-intensity ultrasound to ablate human atherosclerotic plaques and minimize debris size

To investigate whether high-intensity ultrasound can destroy atherosclerotic plaques while sparing the normal arterial wall, 279 normal human aortic sites and 119 fibrous and 193 calcified plaques, obtained from 24 necropsies, were insonified in a water tank, at 20 kHz and at 5 different power intensities, ranging from 68 W/cm 2 (P 1) to 150 W/cm 2 (P 5). These intensities were associated with a total excursion of the ultrasound irradiation apparatus tip from 90 to 268 μm, respectively. Time to perforate normal aortic sites and fibrous and calcified plaques was recorded at each intensity. There was no difference in perforation time between normal aortic sites and fibrous and calcified plaques when high-power levels (P 2 to p 5) were used. However, at the lowest power (P 1), perforation time for the normal aortic wall was significantly longer than for fibrous and calcified plaques: 30 ± 18 seconds (166 observations), 14 ± 7 seconds (p < 0.001) (78 observations) and 12 ± 8 seconds (p < 0.001) (115 observations), respectively. When perforation times for normal vessel wall versus fibrous plaque and normal vessel wall versus calcified plaque from the same necropsy specimen were compared in a pairwise manner, the results were: 29 ± 13 vs 16 ± 7 (p < 0.001) (48 paired observations) and 26 ± 9 vs 10 ± 5 seconds (p < 0.001) (55 paired observations), respectively. Regardless of whether paired or unpaired comparison was applied, no significant difference was found in perforation time between fibrous and calcified plaques. The debris did not differ in size as measured separately for normal sites and fibrous and calcified plaques by a computer-interfaced Channelizer ® and Coulter ® Counter system. A total of 57,863 particles were counted and measured. The mean particle diameter was 7.0 ± 5 μm (range 4.8 to 15.8). Thus, ultrasound may selectively ablate human atherosclerotic plaques at power intensities ≤68 W/cm 2.

Improvement of photosynthesis of vitamin D2 in irradiation apparatus with erythemic lamps

Improvement of photosynthesis of vitamin D2 in irradiation apparatus with erythemic lamps

輸血後移植片対宿主病の予防を目的とする血液製剤へのＸ線照射条件の検討

X-ray irradiation on blood products is a common method to prevent the risk of inducing PTGVHD, and has recently become to be used in Japan. We have tried X-ray irradiation on WB, CRC and PC using HITACHI X-ray Irradiation Apparatus MBR1520R, and studied its practical usefulness.In case of irradiation on blood bags as the minimum dose of 1, 500 rads, these conditions are thought to be practical: 1) the use of 1.0mm Al filter 2) the distance of 550nm from X-ray source 3) irradiation on 4 bags at the same time. But, it has also been noticed that total doses and qualities of X-ray absorbed into blood were different between upper and lower side of the bag. Bloods on upper side absorbed much doses and a wide range of X-ray, on the other hand, bloods on lower side absorbed less doses and hard X-ray.In these conditions, irradiated lymphocytes showed a complete inhibition of thymidine uptake in MLC test, still had 15% of activity in PHA stimulation. The qualities of other blood components have not changed before and after irradition.X-ray irradiation is useful in a routine work of blood center, but problems of proper doses and a uniformity of irradiation are remained to be sloved.

Desorption processes of hydrogen and methane from clean and metal-deposited graphite irradiated by hydrogen ions

Thermal desorption processes of H 2 and CH 4 from clean graphite surfaces and metal-deposited graphite surfaces have been investigated. Thin metal layers of Ti, Cr and Fe on isotropic graphites were prepared by an electron-beam evaporation method. For these specimens, the irradiation and the desorption experiments were performed with the use of an ECR ion irradiation apparatus. The desorption spectra of H 2 and CH 4 from the clean surface had only a single peak at 700 and 800 °C. These peaks were found to originate from the diffusion limited process and to be attributed to the intrinsic nature of graphite. The metal depositions on the graphite surface caused a new desorption peak for H 2 and CH 4 besides the intrinsic peak. The temperature and intensity of the new peak depended on the metal species. The presence of the metals increased the amount of desorbed H 2 for fluences of more than 1 × 10 18 H/ cm 2 but decreased the amount of desorbed CH 4 in the whole fluence range of this study. Fe was most effective to reduce the CH 4 desorption among the three metals.

The chemical response of the photo-electric aerosol sensor (PAS) to different aerosol systems

A comparative study of the response of a photo-electric aerosol sensor (PAS) to different PAH aerosol systems is presented. The photo-electric activity of pure PAH particles as well as of PAH-coated graphite particles (sub-monolayer up to multi-layer coating) is determined with a miniaturized UV irradiation apparatus. The growth of layers is measured by observing the increased penetration through a screen diffusion battery. The results indicate that an analytically useful response is only obtained as long as a monolayer coating is not exceeded. Beside the extent of the π-electron system of the PAH, the molecular packing of the PAH-molecules governs the photo-electric activity.

The chemical response of the photoelectric aerosol sensor (PAS) to different aerosol systems

Abstract A comparative study of the response of a photo-electric aerosol sensor (PAS) to different PAH aerosol systems is presented. The photo-electric activity of pure PAH particles as well as of PAH-coated graphite particles (sub-monolayer up to multi-layer coating) is determined with a miniaturized UV irradiation apparatus. The growth of layers is measured by observing the increased penetration through a screen diffusion battery. The results indicate that an analytically useful response is only obtained as long as a monolayer coating is not exceeded. Beside the extent of the π-electron system of the PAH, the molecular packing of the PAH-molecules governs the photo-electric activity.

Improvement of the photostability of ubidecarenone microcapsules by incorporating fat-soluble vitamins

Ubidecarenone was microencapsulated together with one of the three fat-soluble vitamins, i.e. tocopherol, tocopherol acetate and phytonadione, by the spray-drying method to improve the photostability of ubidecarenone at ordinary and elevated temperatures under intensified ultraviolet irradiation. The irradiation apparatus consisted of a mercury vapor lamp and a grating monochromator with a xenon lamp. All microencapsulated ingredients underwent photolysis following apparent first-order degradation kinetics. The photolytic degradation of ubidecarenone was inhibited most markedly by the incorporation of phytonadione, but no satisfactory inhibition was obtained by tocopherol acetate. The degradation rate constant of ubidecarenone decreased rapidly with the increase in amount of phytonadione, whereas it did not decrease very much with increasing amounts of tocopherol. The competitive degradation effect where the more the percent degradation of vitamin was, the less was that of ubidecarenone was clearly confirmed in phytonadione system irrespective of irradiation wavelength. The inhibitory effects related closely to the photostability and light absorption properties of vitamins added. The protection of ubidecarenone from photolytic degradation could also be achieved at higher of any vitamin. temperatures, but the activation energy was not affected significantly by the incorporation

Removal of dissolved 85Kr by vacuum degassing method.

In the irradiation apparatus where unsealed 85Kr gas is used as an internal radiation source for liquid-phase chemical reaction, the 85Kr gas dissolved in a liquid reactant must be removed after irradiation. Experiments on removal of dissolved 85Kr by the vacuum degassing method were carried out to examine the influence of degassing temperature, initial 85Kr concentration and stirring of a solution on the removal. The liquid reactant used was a water of 500 ml in which 85Kr gas was dissolved. The removal effect became greater with increasing temperature. The dissolved 85Kr concentration after removal decreased exponentially with the reciprocal of degassing temperature. Further, the removal effect was intensely affected by stirring of the solution and was independent of the initial 85Kr concentration. The removal factor of dissolved 85Kr at 33 degrees C reached 5 X 10(3) after a 30 minute lapse.

Photostability of Solid-State Ubidecarenone at Ordinary and Elevated Temperatures under Exaggerated UV Irradiation

□ The photostability of ubidecarenone was investigated. Two irradiation apparatus, a grating monochromator and a high-pressure mercury vapor lamp, were employed at ordinary and elevated temperatures. Both physicochemical and chemical stabilities were significantly affected by irradiation wavelength, with UV light causing the greatest changes. The degree of degradation was a function of the light absorption properties of the substrate and markedly increased when the absorption became >30%. The photolytic degradation followed apparent first-order kinetics at all wavelengths and was promoted with temperature elevation. The Arrhenius plot gave an activation energy in the solid state different from that in the liquid state. These activation energies linearly decreased with increasing intensity of UV light.

Post-operative stereotactic Curie-therapy using the iridium-192 gammamedsr contact irradiation apparatus combined with radio-sensitizers in treating multiform glioblastomas

Experimental investigations on the dimethyl-amino-stilbous carcino-sarcoma of the rat have led to a modified interstitial post-operative Curie-therapy of gliomas in the brain hemispheres following treatment with radio sensitizers. After treatment with the thymine-analogous radio-sensitizers 5-brom-2-desoxyuridine (BUDR) and 5-brom-2-desoxycytidine (BCDR) and desoxyguanosine as well as the anti-metabolites 5-fluor-uracile (FU) and methotrexate (Mtx), there is greater incorporation of the thymine analogues in the DNS of the tumour cells. More than any other combination, BUDR and Mtx effectively sensibilizes the tumour cells. Syncavit and actinomycine-D are also effective. After radio-sensitizing the post-iridium-192 contact irradiation apparatus on 133 patients with gliomas. This treatment lengthened postoperative survival times.

Rapid and Microdetermination of Carbon Monoxide in Blood using Oxygen Electrode and Light Irradiation Apparatus

Rapid and Microdetermination of Carbon Monoxide in Blood using Oxygen Electrode and Light Irradiation Apparatus

The Decay of Potentially Lethal Oxygen-dependent Damage in Fully HydratedBacillus MegateriumSpores Exposed to Pulsed Electron Irradiation

Using a stopped-flow mixing and pulsed irradiation apparatus, a study has been made of the decay, to a harmless form, of radiation-induced species which would otherwise be lethal to spores on contact with oxygen. Aqueous suspensions of Bacillus megaterium spores were irradiated with 600 krad of electrons given over approximately 1 s; at various times after irradiation oxygen in solution was added. As the interval between irradiation and introduction of oxygen increased, the fraction of spores surviving increased. For spores irradiated in a deoxygenated condition the decay of the potentially lethal species, reflected by this change in survival, proceeded as if two parallel first-order reactions with half-lives of 9 and 120 s operate. In contrast, for spores equilibrated with oxygen and then irradiated, the decay is described by a single first-order expression with an associated half-life similar to that of the faster of the two reactions operating in anoxia.

An efficient irradiation apparatus with magnet for wire & cable

An efficient irradiation apparatus with magnet for wire & cable

Problems in neutron dosimetry

A summary of problems in neutron dosimetry is presented. Two categories are distinguished: those which pertain to physical measurements, and those which arise due to the nature of biological systems and the irradiation apparatus utilized, with special emphasis on the radiotherapy situation. The influence of radiation quality on almost all of these problems is discussed.

Über die wirkung des phytochroms beim laubmooskallus II. Sauerstoffmetabolismus und acetylcholinwirkung

The oxygen metabolism is a good parameter for the determination of rapid responses of green moss callus to light. We measured the oxygen uptake with the Warburg method and polarographically with a Clark electrode and the YSI-oxygen monitor. The exposure of dark grown moss callus to red light (5–20 min) induced a rapid increase in O 2 -uptake after switching off the light. The respiration change depends on the exposure duration and the light intensity. During the first 2 or 3 h after irradiation with red light and with red-far red light, the rates of the O 2 -uptake show no differences but after this lag-phase the 2 curves are splitting. The respiration of the red irradiated cells remained higher over a period of 23 h compared to the red — far red irradiated cells. In the latter case the respiration reached the value of the dark control after 20 h. We could reverse the red effect of the rapid respiration change immediately with far red, using an irradiation apparatus with a rhythm of 0.45 s red — far red without a dark-phase. The acetylcholine (ACh) interactions with these light qualities were very complex. ACh was only physiologically active when the cofactor ascorbic acid was present. ATP is an additional cofactor for the ACh action with red — far red induced processes. There are great differences between ACh effects in long time experiments (like our Warburg tests) and in short time ones. ACh had no effect on the oxygen output or uptake when the cells were irradiated with red light, in contrast to the effect occuring with quick alternating red — far red illumination. In this case ACh promotes the oxygen output. This effect is inhibited by eserine. The complex manner of ACh effects is indicated by the results which we got from Warburg experiments. The application of ACh together with the onset of red irradiation has no effect independent of the ATP content of the substrate. We got the opposite results in experiments were we applied the hormone after the red illumination. In this case ACh mimicked a far red effect. ATP in the substrate nullified the ACh-action. We got exactly antagonistic ACh-effects with red — far red light treatments. In this case we had to apply the hormone with the onset of the irradiation. Then ACh mimicked a red light effect but only with ATP as cofactor. The physiological effects of red irradiations in moss callus grown in darkness or in continuous far red light cannot be mimicked by ACh. ACh becomes active after or during the irradiation. Light is necessary for ACh effects. Therefore, we think one cannot consider this hormone as being a special phytochrome hormone.

A sample changer for automatic irradiation apparatus

A sample changer for automatic irradiation apparatus with on-line measurement system has been constructed and used for the study of a short-lived activity accompanied with a longer-lived one. Constructional details and some of the results obtained using this apparatus are presented.

An automatic irradiation apparatus with on-line measurement system for the study of short-lived activities

For the study of short-lived activities produced by (n, γ) reactions, a special pneumatic irradiation apparatus with on-line measurement system has been designed and installed at the through-tube facility of the Kyoto University reactor. With this apparatus the irradiation of a sample and the subsequent nuclear spectroscopic measurements are automatically and cyclically performed. Using this apparatus, singles and coincidence spectra of γ-rays, angular correlations of cascading transitions or lifetimes of excited states have been measured for several short-lived isotopes. Detailed description of the apparatus and some of the results obtained are described.

Levels and transitions in 104Pd from the decay of 104mRh and 104gRh

Singles and coincidence spectra of γ-rays following the decay of 4.41 min 104mRh and 43 sec 104gRh have been studied using Ge(Li) and NaI(Tl) detectors. The γ-rays of 17 transitions in the decay of 104mRh and of 8 transitions in the decay of 104gRh have been observed and their energies and relative intensities have been determined. The negaton decay of the 5 + isomeric state has been found to lead to the levels in 104Pd at 1323.5± 0.7(4 +), 2082.3± 0.6(4 +), 2181.5±0.6(4 +) and 2265.4±0.6 keV (4 +), while the 1 + ground state has been found to decay to the levels at 555.7±0.5(2 +), 1333.6±1.0(0 +), 1341.5±0.4(2 +), 1792.7±0.6(0 +) and 1793.2±1.2 keV in addition to the ground state. Gamma-gamma angular correlations have been measured on 6 cascading transitions in 104Pd using the NaI(Tl)-Ge(Li) coincidence spectrometer and an automatic irradiation apparatus. The spin of the 1333.6 and 1792.7 keV levels has been uniquely determined as 0. The multipolarity of the 785.6 keV 2' +→ 2 + transition has been determined to be E2+ < 1 % M1, as is consistent with the vibrational model description. The M1 — E2 mixing ratios of the transitions from the 4 + states at three-phonon region to the two-phonon 4 + state have been determined. The level structure and transitions in 104Pd are discussed in the light of the vibrational model. The systematic trend of log ft values to the phonon states in Pd isotopes is discussed. It is found that the allowed β-transitions from the 1 + states to the two-phonon 0 + and 2 + states are generally hindered compared with those to the zero- and one-phonon states, while the transitions to the 2 + states at three-phonon region are less hindered compared with those to the two-phonon 2 + states.

Apparatus for the measurement of quantum yields and rates of photochemical reactions.

Abstract— A versatile irradiation apparatus for the quantitative study of photochemical reactions is described, which incorporates a commercial monochromator and utilizes a calibrated thermopile for the continuous measurement of light absorption during irradiation. The operating characteristics are discussed, and illustrative applications are cited. Using this apparatus, the quantum yield of the potassium ferrioxalate actinometer at 366 nm and 25d̀C was determined as 1.27 ± 0.01 for a 6.0 times 10‐3 M solution, in excellent agreement with reported values of 1.26.

Erythropoietic Protoporphyria

Abnormal in vitro red cell photohemolysis can be used as a diagnostic aid for erythropoietic protoporphyria. Photohemolysis is regularly present in erythropoietic protoporphyria and is negligible in normal subjects, in patients with polymorphic light eruption, and in lead poisoning. A simple technique consists of irradiating a suspension of red cells diluted 1:500 in Ringer's solution by using a modified x-ray view box equipped with blacklight fluorescent tubes to serve as the irradiation apparatus. After three hours of exposure presence of photohemolysis is determined by direct visual or by photometric examination of the supernatant fluid. The technique does not involve a chemical or fluorometric analysis.