The relation between cytological abnormalities and interphase chromosome volume in plants growing in a high radiation area

1971 ◽  
Vol 11 (2) ◽  
pp. 175-178 ◽  
Author(s):  
G.G. Nayar ◽  
K.P. George ◽  
A.R. Gopal-Ayengar
Keyword(s):  
High Radiation ◽  
Interphase Chromosome ◽  
Cytological Abnormalities ◽  
Radiation Area

CYTOGENETIC EFFECTS OF 2,4-D AND AMITROLE IN RELATION TO NUCLEAR VOLUME AND DNA CONTENT IN SOME HIGHER PLANTS

1972 ◽  
Vol 14 (4) ◽  
pp. 773-783 ◽  
Author(s):  
T. Mohandas ◽  
W. F. Grant
Keyword(s):  
Hordeum Vulgare ◽  
Nuclear Dna ◽  
Higher Plants ◽  
Positive Control ◽  
Root Tip ◽  
Interphase Chromosome ◽  
Dna Values ◽  
Cytological Abnormalities ◽  
Centaurea Jacea ◽  
Chrysanthemum Leucanthemum

The cytological effects of 2,4-D and amitrole were studied for 12 species (Tradescantia clone 02, Allium cepa, Vicia faba, Triticum aestivum, T. dicoccum, Hordeum vulgare, Secale cereale, Centaurea jacea, Cirsium vulgare, Chrysanthemum leucanthemum, Plantago major and Erigeron canadensis). Ethyl methane sulfonate (EMS) was used as a positive control. The cytological abnormalities induced in root-tip cells by both 2,4-D and amitrole included chromosome bridges, fragments, lagging chromosomes, and chromatin bodies; 2,4-D also induced chromosome contraction, and C-mitoses. Studies following seed treatments of Hordeum vulgare on M2 seedlings showed that 2,4-D and EMS induced albina mutants. Interphase nuclear volumes of the various species were measured from root-tip meristems. Nuclear DNA values were determined cytophotometrically for seven species. The relative DNA values were found to be positively correlated with nuclear volumes. The lack of any clear relationship between the number of cytological abnormalities induced by the chemicals and the nuclear and interphase chromosome volumes of the plants probably reflects a lack of synchrony of the treated cell population.

scholarly journals HIGH BACKGROUND AREA FOR RADIATION EDUCATION

2019 ◽  
Vol 184 (3-4) ◽  
pp. 294-297 ◽  
Author(s):  
N Matsuda ◽  
N Fukuda ◽  
M Yamauchi ◽  
Y Tsunoyama ◽  
S Tomita ◽  
...  
Keyword(s):  
Environmental Samples ◽  
Real Life ◽  
Educational Effectiveness ◽  
High Radiation ◽  
High Background ◽  
Trial Experience ◽  
Tottori Prefecture ◽  
Radiation Area ◽  
Radiation Education ◽  
Background Area

Abstract This paper describes our trial experience of the use of high radiation area for radiation education. We used environmental samples collected from the high radiation area in Fukushima prefecture and India, for the practice of radiation measurement and health risk assessment in Nagasaki University Medical School. We also carried out the field monitoring seminar for students in the existing exposure areas in Tottori prefecture and the Yamakiya observatory in Fukushima. Although the evaluation of educational effectiveness is still underway, both types of education appeared attractive for the students mostly due to the exposure from natural environment in our real life which was not achieved by using an artificial radiation source in a classroom.

Investigation on Influence Mechanism of Wall Coating on Infrared Radiation Signature of Serpentine Nozzle

2020 ◽  
Author(s):  
Jie Shi ◽  
Li Zhou ◽  
Zhanxue Wang ◽  
Jingwei Shi
Keyword(s):  
Radiation Intensity ◽  
Infrared Radiation ◽  
Infrared Detector ◽  
Exhaust System ◽  
Nozzle Wall ◽  
High Radiation ◽  
Indirect Transmission ◽  
Influence Mechanism ◽  
Radiation Transmission ◽  
Radiation Area

Abstract Stealth performance is one of the most important factors to evaluate the technical level of modern battleplane. Serpentine nozzle can block the direct radiation transmission path between the high-temperature components in exhaust system and the infrared detector, thus suppressing the infrared radiation signature. However, due to the reflection characteristics of nozzle wall, this method can also cause indirect transmission of infrared radiation through the wall reflection to form a local high radiation area. Motivated by previous researches on the application of serpentine nozzle wall coating in electromagnetic radiation suppression. Wall coating is applied to serpentine nozzle to suppress infrared radiation intensity in this paper. Aiming at the situation of turbofan engine using serpentine nozzle, the influence mechanism of coating position, area and emissivity of serpentine nozzle on infrared radiation signature is calculated and analyzed, and the scheme of wall coating which has the least coating area and can effectively suppress infrared radiation transmission is also studied. The results show that reducing wall coating emissivity will strengthen the indirect transmission of infrared radiation, then cause the increase of exhaust system infrared radiation intensity, while increasing wall coating emissivity will reduce wall coating reflectivity, and the local high radiation area caused by indirect radiation transmission can be effectively prevented. The research also found that the infrared radiation signature of exhaust system can be effected only when the emissivity adjustment of serpentine nozzle wall which can be detected directly by infrared detector. After adopting the optimized wall emissivity coating scheme, the infrared radiation intensity of serpentine nozzle for turbofan can be reduced by 51.3% on the original basis while the coating area only accounts for 25.1% of the nozzle area.

Nuclear Envelope Dynamics During Mitosis

1988 ◽  
Vol 46 ◽  
pp. 224-225
Author(s):  
Brian Burke
Keyword(s):  
Nuclear Envelope ◽  
Membrane Vesicles ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Animal Cells ◽  
Interphase Chromosome ◽  
Lamin B ◽  
Chromosome Architecture ◽  
Complex Membrane ◽  
Pore Complexes

The nuclear envelope is a complex membrane structure that forms the boundary of the nuclear compartment in eukaryotes. It regulates the passage of macromolecules between the two compartments and may be important for organizing interphase chromosome architecture. In interphase animal cells it forms a remarkably stable structure consisting of a double membrane ouerlying a protein meshwork or lamina and penetrated by nuclear pore complexes. The latter form the channels for nucleocytoplasmic exchange of macromolecules, At the onset of mitosis, however, it rapidly disassembles, the membranes fragment to yield small vesicles and the lamina, which is composed of predominantly three polypeptides, lamins R, B and C (MW approx. 74, 68 and 65 kDa respectiuely), breaks down. Lamins B and C are dispersed as monomers throughout the mitotic cytoplasm, while lamin B remains associated with the nuclear membrane vesicles.

Projected Structure of the Surface Protein of Sulfolobus Spec. B12 Determined to a Resolution of 1.0 NM by Cryo-Electronmicroscopy

1990 ◽  
Vol 48 (1) ◽  
pp. 102-103
Author(s):  
G. Lembcke ◽  
F. Zemlin
Keyword(s):  
Low Dose ◽  
Maximum Dose ◽  
Three Dimensional ◽  
Surface Protein ◽  
Protein S ◽  
Radiation Sensitivity ◽  
Specimen Preparation ◽  
Molecular Architecture ◽  
High Radiation ◽  
Fritz Haber

The thermoacidophilic archaebacterium Sulfolobus spec. B12 , which is closely related to Sulfolobus solfataricus , possesses a regularly arrayed surface protein (S-layer), which is linked to the plasma membrane via spacer elements spanning a distinct interspace of approximately 18 nm. The S-layer has p3-Symmetry and a lattice constant of 21 nm; three-dimensional reconstructions of negatively stained fragments yield a layer thickness of approximately 6-7 nm.For analysing the molecular architecture of Sulfolobus surface protein in greater detail we use aurothioglucose(ATG)-embedding for specimen preparation. Like glucose, ATG, is supposed to mimic the effect of water, but has the advantage of being less volatile. ATG has advantages over glucose when working with specimens composed exclusively of protein because of its higher density of 2.92 g cm-3. Because of its high radiation sensitivity electromicrographs has to be recorded under strict low-dose conditions. We have recorded electromicrographs with a liquid helium-cooled superconducting electron microscope (the socalled SULEIKA at the Fritz-Haber-lnstitut) with a specimen temperature of 4.5 K and with a maximum dose of 2000 e nm-2 avoiding any pre-irradiation of the specimen.

PET/CT

2005 ◽  
Vol 44 (S 01) ◽  
pp. S51-S57 ◽  
Author(s):  
T. Beyer ◽  
G. Brix
Keyword(s):  
Diagnostic Accuracy ◽  
Radiation Exposure ◽  
Dose Reduction ◽  
Pet Imaging ◽  
Clinical Studies ◽  
Review Article ◽  
Whole Body ◽  
High Radiation ◽  
Radiation Burden ◽  
Pet Ct

Summary:Clinical studies demonstrate a gain in diagnostic accuracy by employing combined PET/CT instead of separate CT and PET imaging. However, whole-body PET/CT examinations result in a comparatively high radiation burden to patients and thus require a proper justification and optimization to avoid repeated exposure or over-exposure of patients. This review article summarizes relevant data concerning radiation exposure of patients resulting from the different components of a combined PET/CT examination and presents different imaging strategies that can help to balance the diagnostic needs and the radiation protection requirements. In addition various dose reduction measures are discussed, some of which can be adopted from CT practice, while others mandate modifications to the existing hardand software of PET/CT systems.

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