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441.
Andrea Hille Hana Hofman-Hüther Elna Kühnle Barbara Wilken Margret Rave-Fränk Heinz Schmidberger Patricia Virsik 《Radiation and environmental biophysics》2010,49(1):27-37
The aim of the study was to compare the spontaneous and ex vivo radiation-induced chromosomal damage in lymphocytes of untreated
prostate cancer patients and age-matched healthy donors, and to evaluate the chromosomal damage, induced by radiotherapy,
and its persistence. Blood samples from 102 prostate cancer patients were obtained before radiotherapy to investigate the
excess acentric fragments and dicentric chromosomes. In addition, in a subgroup of ten patients, simple exchanges in chromosomes
2 and 4 were evaluated by fluorescent in situ hybridization (FISH), before the onset of therapy, in the middle and at the
end of therapy, and 1 year later. Data were compared to blood samples from ten age-matched healthy donors. We found that spontaneous
yields of acentric chromosome fragments and simple exchanges were significantly increased in lymphocytes of patients before
onset of therapy, indicating chromosomal instability in these patients. Ex vivo radiation-induced aberrations were not significantly
increased, indicating proficient repair of radiation-induced DNA double-strand breaks in lymphocytes of these patients. As
expected, the yields of dicentric and acentric chromosomes, and the partial yields of simple exchanges, were increased after
the onset of therapy. Surprisingly, yields after 1 year were comparable to those directly after radiotherapy, indicating persistence
of chromosomal instability over this time. Our results indicate that prostate cancer patients are characterized by increased
spontaneous chromosomal instability. This instability seems to result from defects other than a deficient repair of radiation-induced
DNA double-strand breaks. Radiotherapy-induced chromosomal damage persists 1 year after treatment. 相似文献
442.
Jos Eduardo Pereira Wilken Bicudo 《Journal of morphology》1986,188(2):251-255
The surface areas of the tracheal and cuticular systems of Peripatus acacioi individuals of different body weights were determined by morphometric analysis. The results demonstrate that both surfaces increase with body weight, although the observed increase in the surface area of the tracheal system appears to be at a greater rate. The slopes of the two regression lines obtained are statistically different. It is therefore suggested that the preferential route for water loss in P. acacioi is related to the size of the animals, i.e., smaller onychophorans would lose water mainly through the cuticle, while larger ones would lose water through the respiratory surfaces. 相似文献
443.
Qin Xu Ivo Peters Sam Wilken Eric Brown Heinrich Jaeger 《Journal of visualized experiments : JoVE》2014,(85)
In the field of fluid mechanics, many dynamical processes not only occur over a very short time interval but also require high spatial resolution for detailed observation, scenarios that make it challenging to observe with conventional imaging systems. One of these is the drop impact of liquids, which usually happens within one tenth of millisecond. To tackle this challenge, a fast imaging technique is introduced that combines a high-speed camera (capable of up to one million frames per second) with a macro lens with long working distance to bring the spatial resolution of the image down to 10 µm/pixel. The imaging technique enables precise measurement of relevant fluid dynamic quantities, such as the flow field, the spreading distance and the splashing speed, from analysis of the recorded video. To demonstrate the capabilities of this visualization system, the impact dynamics when droplets of non-Newtonian fluids impinge on a flat hard surface are characterized. Two situations are considered: for oxidized liquid metal droplets we focus on the spreading behavior, and for densely packed suspensions we determine the onset of splashing. More generally, the combination of high temporal and spatial imaging resolution introduced here offers advantages for studying fast dynamics across a wide range of microscale phenomena. 相似文献
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