共查询到20条相似文献,搜索用时 15 毫秒
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Marcelino Cereijido 《Biological Rhythm Research》2013,44(2):107-115
The steady flow of solar energy through prebiotic chemical systems forced them to undergo material cycles, and this cycling was inherited by living organisms. Organisms whose cycling synchronized with periodic phenomena, such as day/night and seasonal variations were favored. At a later stage, evolution also favored organisms that, besides of a synchronized cycling, developed a ‘sense of time’ to cope with non-cyclic and unique events in the environment. In the case of human beings, this ‘sense of time’ was used to detect causal chains (cause → effect), combine them to produce dynamic models of reality, and transform real time scales into mental time scales (it takes a moment to remember a year-long phenomenon). The ‘sense of time’ constituted a decisive evolutive advantage, because it enables humans to analyze a multitude of future possibilities, and choose the most promising one. Yet ‘sense of time’ is just an empty metaphore, because it is not a true ‘sense’, and we ignore what ‘time’ really is. Most scientific disciplines simply take for granted that there is a ‘time flowing from future to past’. Biologists instead, cannot adopt this attitude because ‘time’ may very well be an intrinsic property of our mind, i.e., a peculiar aspect of brain physiology. 相似文献
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确保课堂探究活动的时间和质量,是落实"倡导探究性学习"的课程理念的前提.真正有价值的课堂活动需要学生思维的参与,以实例说明,应通过全程备课,把握课程标准的基本要求;通过精选、整合、深挖、拓展,让每一个活动承栽更多的内涵;通过预设多种方式,灵活组合,生成更多的活动机会等,提升课堂活动的内在思维品质,使课堂活动成为知识、能力、情感的有效栽体,以解决活动时间不足、活动效益不高的问题. 相似文献
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Eĭngorin MIa 《Radiatsionnaia biologiia, radioecologiia / Rossi?skaia akademiia nauk》2002,42(6):628-631
In work, on the basis of known base biological laws, the new natural three-dimensional designs are under construction: codonogram and aminogram. Codonogram and aminogram have revealed the new laws of coding and constructions in molecular biology. The secondary coding codonogram, at the expense of redundancy, has enabled for DNA, RNA, and mRNA to construct the hidden coding layers (HLC). HLC are constructed on a base of pirimidine and purine. In interaction with ferments HLC, should guarantee: addressation, synchronization, correction and other functional transformations of a gene. Radiation can damage a layer mRNA of synthesis protein, hidden layers of coding and structure of the ferments of the cell. In work are given: kodonogram, aminogram UGC, basis of construction HLC, the references to the literature with an example of decoding. 相似文献
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Bezlepkin VG Kirillova EN Zakharova ML Pavlova OS Lomaeva MG Fomenko LA Antipova VN Gaziev AI 《Radiatsionnaia biologiia, radioecologiia / Rossi?skaia akademiia nauk》2011,51(1):20-32
Genome variability and changes in immune homeostasis, induced in man in the course of long-term industrial contact with ionizing radiation (IR) sources were studied by using unique biomaterials stored in the Radiobiological Repository for Human Tissues at the Southern Urals Biophysics Institute, FMBA. The biomaterials, peripheral blood samples and blood DNA were obtained from the "Mayak" PA employers occupationally exposed to prolonged external gamma-radiation and/or internal alpha-radiation from incorporated 239Pu in a wide range of accumulated doses. A significant increase in the polymorphism of microsatellite-associated peripheral blood DNA repeats was revealed in a group of persons with accumulated doses of external gamma-radiation above 2.0 Gy, as well as in the descendants of parents with preconceptive doses of higher than 2.0 Gy. In persons whose parents had a preconceptive dose above 2.0 Gy, an increase in the gene p53 mutation rate was observed, and descendants of persons with dose of 3.0 Gy and higher showed mtDNA heteroplasmy, regardless of the sex of an exposed parent. Changes in the expression of membrane markers for the effector and regulatory T-lymphocytes depending on radiation type and dose load were determined. The growth factor level variations (TGF-beta1, EGF, HGF, FGF) in peripheral blood serum in persons exposed to radiation from gamma- or alpha-sources, allow us to consider them as biomarkers of radiation-induced disturbances in immune homeostasis. The concentration changes of TGF-beta1, apoptosis proteins (p53, TPA-cyk, sAPO-1/Fas), and the adhesion molecule sCD27 in the case of cardiovascular diseases in the serum of both irradiated and non-irradiated "Mayak" PA employers point to the information value of these immune response characteristics as specific biomarkers of cardiac disorders. It is proposed that the revealed changes in immune homeostasis and in the variability of somatic cell genome may provoke development of tumors and cardiovascular diseases in man in delayed periods after prolonged exposure to IR. 相似文献
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M. COHEN 《The Annals of applied biology》1971,69(1):1-9
The suitabilities of eleven chemical aphicides were compared for application to plants on which biological control of Tetranychus urticae by Phytoseiulus persimilis was in progress. It was concluded that currently used aphicides offer insufficient selectivity to provide a basis for integrated control programmes, although some older insecticides may have value. 相似文献
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The soliton model of charge and energy transport in biological macromolecules is used to suggest one of the possible mechanisms for electromagnetic radiation influence on biological systems. The influence of the electromagnetic field (EMF) on molecular solitons is studied both analytically and numerically. Numerical simulations prove the stability of solitons for fields of large amplitude, and allow the study of emission of phonons. It is shown that in the spectra of biological effects of radiation there are two characteristic frequencies of EMFs, one of which is connected with the most intensive energy absorption and emission of sound waves by the soliton, and the other of which is connected with the soliton photodissociation into a delocalized state. 相似文献
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Ron E 《Radiation research》2000,154(6):737-738
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Sleep-enhancing effects of far-infrared radiation in rats 总被引:2,自引:0,他引:2
Unrestrained male rats continuously exposed to far-infrared radiation exhibited a significant increase in slow wave sleep (SWS) during the light period but not in the dark period. The change was largely due to the elevated occurrence of SWS episodes but not to the prolongation of their duration. Paradoxical sleep was not affected throughout the observation period except for a significant decrease at the end of the dark period. Thus the far-infrared radiation exerted a sleep modulatory effect closely related to the circadian activity-rest cycle. 相似文献
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P Oftedal 《Mutation research》1991,258(2):191-205
It is theorized that biological responses to ionizing radiation in the low dose range are determined according to a doubly dichotomous pattern. Energy depositions fall into 2 categories: events at thermal energy levels where they may be experienced by cells as rates even at background exposure conditions, and events at energy levels of the order of 10-100 eV where damage to DNA may be caused. Variations in background exposure intensity may or may not lead preemptively to changes in the cell's capacity for response to radiation damage. High-level energy depositions lead post hoc to an initial stabilizing reaction largely leading to the fixation of the initial DNA damage, and to a subsequent restorative or palliative repair process. This model entails reinterpretation of some experimental results. The model has implications for the relationship between scientific analysis of low-dose effects and the regulatory needs for simplicity and homogeneity in risk evaluation. This represents a new challenge for the acceptability of radiation protection norms. 相似文献
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Space radiation effects and microgravity 总被引:5,自引:0,他引:5
Humans in space are exposed both to space radiation and microgravity. The question whether radiation effects are modified by microgravity is an important aspect in risk estimation. No interaction is expected at the molecular level since the influence of gravity is much smaller than that of thermal motion. Influences might be expected, however, at the cellular and organ level. For example, changes in immune competence could modify the development of radiogenic cancers. There are no data so far in this area. The problem of whether intracellular repair of radiation-induced DNA lesions is changed under microgravity conditions was recently addressed in a number of space experiments. The results are reviewed; they show that repair processes are not modified by microgravity. 相似文献