scholarly journals Der Einfluß der Temperatur auf die Strahlenempfindlichkeit von Ribonuclease

1967 ◽  
Vol 22 (3) ◽  
pp. 313-320 ◽  
Author(s):  
Wolfgang Günther ◽  
Horst Jung
Keyword(s):  
Gamma Radiation ◽  
Cross Section ◽  
Gamma Rays ◽  
Room Temperature ◽  
Bacterial Spores ◽  
Kcal Mole ◽  
Biological Objects ◽  
The Cross ◽  
Apparent Activation Energies ◽  
Mev Protons

The radiosensitivity of dry ribonuclease was determined at various temperatures ranging from 90 °K to 300 °K and using 60Co gamma-radiation, 2 MeV protons, and 2 MeV deuterons. The cross section for the inactivation of RNase S (T) is, in this range, given as a function of temperature byS(T) =S0+S1·e-Ea/RT.For inactivation of ribonuclease with Co gamma-rays we found S0=0 and Ea=1000 cal/mole; S1= =0.125 Mrad-1 when irradiation is carried out in vacuo, and S1=0.265 Mrad-1 in oxygen. With protons and deuterons the following values were determined: S0=1.28·10-14 cm2, S1=19.5·10-14 cm2, Ea=1050 cal/mole for 2 MeV protons; S0=2.45·10-14 cm2, S1=31·10-14 cm2, and Ea = 1050 cal/mole for 2 MeV deuterons. Furthermore, by analysis of some recent data from the literature we found that the cross section for inactivation by ionizing radiation of various enzymes, bacteriophages, and bacterial spores in the range from 4 °K to temperatures higher than room temperature can satisfactorily be described by the more general equationS(T) =S0+S1·e-E₁/RT+S2·e-E₂/RT,with E1=1 kcal/mole and E2=4 kcal/mole being constant for all objects and for all circumambient conditions tested. This correlation between inactivation cross section S (T) and temperature T shows three mechanisms of inactivation to occur in biological objects: one (S0) being independent of temperature, while the two others have apparent activation energies of 1 kcal/mole and 4 kcal/mole, respectively.

scholarly journals Strahleninaktivierung von Ribonuclease bei erhöhten Temperaturen und unterschiedlichen Dosisraten

1968 ◽  
Vol 23 (7) ◽  
pp. 949-952 ◽  
Author(s):  
Klaus Kürzinger ◽  
Horst Jung
Keyword(s):  
Dose Rate ◽  
Cross Section ◽  
Room Temperature ◽  
Activation Energies ◽  
The Other ◽  
Radical Reactions ◽  
Kcal Mole ◽  
Apparent Activation Energies ◽  
Mev Protons ◽  
Dose Rate Effect

The radiosensitivity of dry ribonuclease was determined at various temperatures between 120 °K and 440 °K using 2 MeV protons. Within this temperature range the inactivation cross section S (T) of ribonuclease may be described as a function of temperature by the expression S(T) = (1.28 + 16·e-1000/RT+14000·e-6500/7RT)·10-14 cm2 .This result indicates that the observed radiation damage to ribonuclease is produced by three different mechanisms, one being independent of temperature, the other two having apparent activation energies of 1 kcal/mole and 6.5 kcal/mole, respectively. From these relatively small activation energies the conclusion may be drawn that radical reactions contribute to the inactivation of enzymes in the dry state. Experiments with Co gamma radiation showed that the radiosensitivity of ribonuclease at 77 °K depends on dose rate; at room temperature a dose rate effect was not observed.

scholarly journals Unbeeinflußbarkeit ihrer Wirkung auf Ribonuclease durch Cystamin und tiefe Temperaturen

1966 ◽  
Vol 21 (12) ◽  
pp. 1165-1170 ◽  
Author(s):  
H. Jung
Keyword(s):  
Cross Section ◽  
Low Temperatures ◽  
Room Temperature ◽  
High Efficiency ◽  
Reduction Factor ◽  
Biological Damage ◽  
Nuclear Collisions ◽  
Different Temperatures ◽  
Fast Protons ◽  
Mev Protons

Slow protons having energies below 1.5 keV dissipate their kinetic energy in matter through elastic nuclear collisions. By this process atoms are displaced out from their original positions in macromolecules. This was recently shown to cause biological damage with high efficiency. Experiments are described to test the possibility of modifying the sensitivity of ribonuclease towards elastic collisions by protective agents and by low temperatures. When cystamine is present during irradiation dry ribonuclease is protected against the action of “ionizing” fast protons (2 MeV), the dose reduction factor being 1.8. But no protection is observed when inactivation is achieved by elastic nuclear collisions (proton energy 1 keV and 1.4 keV). Similar results were obtained when the irradiations were carried out at different temperatures. Using 2 MeV protons the radiosensitivity of ribonuclease was found to be 3 times higher at room temperature than at 125 °K, but when using slow protons of 1.4 keV energy the inactivation cross section turned out to be independent of temperature. This shows that the action of elastic nuclear collisions can be modified neither by cystamine nor by low temperatures.

Quantal inversion of the cross section for the elastic scattering of 200 MeV protons fromC12

1994 ◽  
Vol 49 (4) ◽  
pp. 2177-2181 ◽  
Author(s):  
L. J. Allen ◽  
K. Amos ◽  
P. J. Dortmans
Keyword(s):  
Elastic Scattering ◽  
Cross Section ◽  
The Cross ◽  
Mev Protons

High-Pressure Torsion for Ring Samples in Different Thicknesses

2010 ◽  
Vol 667-669 ◽  
pp. 51-56 ◽  
Author(s):  
Hideaki Iwaoka ◽  
Yosuke Harai ◽  
Z. Horita
Keyword(s):  
High Pressure ◽  
Cross Section ◽  
Room Temperature ◽  
Rotation Speed ◽  
High Pressure Torsion ◽  
Upper Limit ◽  
The Cross

High-pressure torsion (HPT) was conducted with ring samples of pure Al (99.99%) having different thicknesses. They were cut from an Al plate with 10 mm thickness to dimensions having inner and outer diameters of 23 and 30 mm with thicknesses of 2 mm or 4 mm. HPT was conducted at room temperature under a pressure of 1 GPa at a rotation speed of 1 rpm. It is shown that the strain was introduced more intensely in the mid part on the cross section. This strained region extended with increasing number of revolution and covered throughout the cross section in the 2 mm thickness ring after 30 revolutions. The intense-strained region extended to ~3 mm in the 4 mm thickness ring after 30 revolutions but remains almost the same even after 100 revolutions. The thickness of ~3 mm may be an upper limit to achieve homogeneous introduction of the strained region throughout the cross section.

Thermal Shock Behaviors of Laser Cladding NiCoCrAlY Coatings Strengthened by Nanometric SiC Particles

2010 ◽  
Vol 431-432 ◽  
pp. 5-8
Author(s):  
Hong Yu Wang ◽  
Dun Wen Zuo ◽  
Xiang Feng Li ◽  
Yong Jun Chen
Keyword(s):  
Oxide Scale ◽  
Thermal Shock ◽  
Cross Section ◽  
Co2 Laser ◽  
Room Temperature ◽  
Internal Crack ◽  
Thermal Shock Test ◽  
Shock Test ◽  
Sic Particles ◽  
The Cross

Three NiCoCrAlY coatings strengthened by different contents of nano-SiCp (nanometric SiC particles)were prepared on Ni-based superalloy substrates using crosscurrent CO2 laser, and the thermal shock test of these coatings was conducted by cycling between 1050°C and room temperature (10-15°C). The spalled area in the oxide scale of coatings after 10 thermal shock cycles and the thermal shock cracks in the cross-section of coatings after 100 thermal shock cycles were investigated using SEM, OM, and other means. The results show that the thermal shock resistances of NiCoCrAlY coatings are improved after adding nano-SiCp. Among nano-SiCp-added coatings, the coating added with 1.0 wt% nano-SiCp performs best. After 10 thermal shock cycles, there is a slight spallation whose area is only 2.65% in the oxide scale of the coating; after 100 thermal shock cycles, no internal crack is observed in the cross-section, and the amount and size of propagating cracks are slight.

Cross section of direct three-body breakup of 9Be for 1576-keV gamma rays

1983 ◽  
Vol 61 (11) ◽  
pp. 1579-1581 ◽  
Author(s):  
M. Fujishiro ◽  
K. Okamoto ◽  
T. Tsujimoto
Keyword(s):  
Cross Section ◽  
Gamma Rays ◽  
Cluster Model ◽  
Theoretical Estimate ◽  
Γ Rays ◽  
The Cross ◽  
Three Body

Using 1576-keV γ-rays from 142Pr, the cross section of the direct three-body breakup of 9Be was measured and found to be (4.0 ± 1.8) × 10−1 μb. This result is in approximate agreement with Salyers' theoretical estimate based upon a cluster model of 9Be.

Texture Heterogeneity in ECAP Deformed Copper

2010 ◽  
Vol 160 ◽  
pp. 47-54 ◽  
Author(s):  
Werner Skrotzki ◽  
Christine Tränkner ◽  
Robert Chulist ◽  
Benoît Beausir ◽  
Satyam Suwas ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Equal Channel Angular Pressing ◽  
Cross Section ◽  
Material Flow ◽  
Room Temperature ◽  
High Energy ◽  
Polycrystalline Copper ◽  
Angular Pressing ◽  
The Cross

Polycrystalline copper of 4N purity has been deformed by equal channel angular pressing at room temperature using route BC. Local textures have been measured by high-energy synchrotron radiation along 3 lines in the cross section from the top to the bottom of the billets. The texture heterogeneity observed in the cross section is presented for 2 passes and discussed with regard to friction-affected material flow.

Gamma-activation analysis of selenium at the electron accelerator “Mikrotron-ST”

2020 ◽  
Vol 6 ◽  
pp. 18-22
Author(s):  
V.I. Tovtin ◽  
◽  
V.N. Kolokoltsev ◽  
N.N. Dogadkin ◽  
E.E. Starostin ◽  
...  
Keyword(s):  
Activation Analysis ◽  
Gamma Radiation ◽  
Gamma Rays ◽  
Electron Accelerator ◽  
Room Temperature ◽  
Gamma Ray ◽  
Polyethylene Capsule ◽  
Mechanical Dispersion ◽  
Quantum Radiation ◽  
Energy Gamma

In this work, an activation analysis of selenium under its irradiation with bremsstrahlung gamma radiation on a cyclic electron accelerator “Microtron-sT” with an energy of 21 MeV is carried out irradiation was performed at room temperature for 1 h, the gamma-ray intensity was ~ 5·1013 γ/s. Irradiation was carried out on two types of state of the samples (Se) in the form of granules of the (osch), weight 5-10 mg, and microparticles (powder) obtained by mechanical dispersion. Samples in the state of microparticles were suspended in distilled water, in separate polyethylene capsule. On each sample, after irradiation with bremsstrahlung gamma radiation, the spectra of quantum radiation of radionuclides were measured. The measurements were carried out repeatedly in order to observe a decrease in the activity of the samples and their energy gamma spectrum. From the results obtained, it can be seen that all radionuclides are formed on selenium nuclei with different mass numbers by reactions: (γ, n), (γ, p), (γ, 2n), (γ, p + n). The half-life of (T1/2) in identified radionuclides is within 3.9 minutes — 119.8 days. The energy of emitted quanta by radionuclides is equal to from 121.1 to 657 keV. The radiation intensity of radionuclide gamma rays is in the range: 0.25-99.0%.

Observables in

1984 ◽  
Vol 62 (11) ◽  
pp. 1064-1071 ◽  
Author(s):  
M. L. Rustgi ◽  
R. D. Nunemaker ◽  
R. Vyas
Keyword(s):  
Cross Section ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Nucleon Nucleon ◽  
Asymmetry Function ◽  
The Cross

A summary of the results obtained by the authors on the cross section, polarization, and asymmetry function for [Formula: see text] at medium and low gamma-ray energies is presented. The results on the disintegration of the oriented deuterons by unpolarized gamma rays illustrate the differences arising in two of the observables from the use of two different nucleon–nucleon potentials.

THE CAPTURE OF PROTONS BY DEUTERONS

1962 ◽  
Vol 40 (4) ◽  
pp. 402-411 ◽  
Author(s):  
G. M. Griffiths ◽  
E. A. Larson ◽  
L. P. Robertson
Keyword(s):  
Angular Distribution ◽  
Total Cross Section ◽  
Energy Dependence ◽  
Cross Section ◽  
Gamma Rays ◽  
Proton Energy ◽  
P Wave ◽  
S Wave ◽  
Proton Capture ◽  
The Cross

The cross section and angular distribution of gamma rays for the reaction D(p,γ)He3 have been measured for proton energies from 275 kev to 1.75 Mev. For 275-kev protons the total cross section is 0.97 ± 0.11 microbarns and for 985-kev protons it is 3.5 ± 0.38 microbarns. The angular distribution has the form (sin2θ+b) where b is small. b is found to increase with decreasing proton energy, contrary to some previous results from this laboratory, and the energy dependence of b and of the cross section suggests that the sin2 θ part of the cross section is due to the capture of p-wave protons and the b part is due to s-wave proton capture.

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