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Savulescu J 《Bioethics》2002,16(6):508-529
One objection to embryonic stem (ES) cell research is that it 'cannibalizes' human beings, that is, kills some human beings to benefit others. I grant for argument's sake that the embryo is a person. Nonetheless, killing it may be justified. I show this through the Embryonic Stem Cell Lottery. Whether killing a person is justified depends on: (1) whether innocent people at risk of being killed for ES cell research also stand to benefit from the research and (2) whether their overall chances of living are higher in a world in which killing and ES cell research is conducted. I call this kind of killing 'risk reductive.' 相似文献
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Azzone GF 《History and philosophy of the life sciences》2003,25(2):211-241
The last two centuries have been the centuries of the discovery of the cell evolution: in the XIX century of the germinal cells and in the XX century of two groups of somatic cells, namely those of the brain-mind and of the immune systems. Since most cells do not behave in this way, the evolutionary character of the brain-mind and of the immune systems renders human beings formed by t wo different groups of somatic cells, one with a deterministic and another with an indeterministic (say Darwinian) behavior. An inherent consequence is that of the generation, during ontogenesis, of a dual biological identity. The concept of the dual biological identity may be used to explain the Kantian concept of the two metaphysical worlds, namely of the causal necessity and of the free will (Azzone, 2001). Two concepts, namely those of complex adaptive systems (CAS) and of emergence (Holland, 2002), are useful tools for understanding the mechanisms of adaptation and of evolution. The concept of complex adaptive systems indicates that living organisms contain series of stratified components, denoted as building blocks, forming stratified layers of increasing complexity. The concept of emergence implies the use of repeating patterns and of building blocks for the generation of structures of increasing levels of complexity, structures capable of exchanging communications both in the top-down and in the bottom-up direction. Against the concept of emergence it has been argued that nothing can produce something which is really new and endowed of causal efficacy. The defence of the concept of emergence is based on two arguments. The first is the interpretation of the variation-selection mechanism as a process of generation of information and of optimization of free energy dissipation in accord with the second principle of thermodynamics. The second is the objective evidence of the cosmological evolution from the Big Bang to the human mind and its products. Darwin has defended the concept of the continuity of evolution. However evolution should be considered as continuous when there is no increase of information and as discontinuous when there is generation of new information. Examples of such generation of information are the acquisition of the innate structures for language and the transition from absence to presence of morality. There are several discontinuity thresholds during both phylogenesis and ontogenesis. Morality is a relational property dependent on the interactions of human beings with the environment. Piaget and Kohlberg have shown that the generation of morality during childhood occurs through several stages and is accompanied by reorganization of the child mental organization. The children respect the conventions in the first stage and gradually generate their autonomous morality. The transition from absence to presence of morality, a major adaptive process, then, not only has occurred during phylogenesis but it occurs again in every human being during ontogenesis. The religious faith does not provide a logical justification of the moral rules (Ayala, 1987) but rather a psychological and anthropological justification of two fundamental needs of human beings: that of rendering Nature an understandable entity, and that of increasing the cooperation among members of the human societies. The positive effects of the altruistic genes in the animal societies are in accord with the positive effects of morality for the survival and development of the human societies. 相似文献
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Mauricio Arias Lindsey J. McDonald Evan F. Haney Kamran Nazmi Jan G. M. Bolscher Hans J. Vogel 《Biometals》2014,27(5):935-948
Lactoferrin (LF) is an important antimicrobial and immune regulatory protein present in neutrophils and most exocrine secretions of mammals. The antimicrobial activity of LF has been related to the presence of an antimicrobial peptide sequence, called lactoferricin (LFcin), located in the N-terminal region of the protein. The antimicrobial activity of bovine LFcin is considerably stronger than the human version. In this work, chimera peptides combining segments of bovine and human LFcin were generated in order to study their antimicrobial activity and mechanism of action. In addition, the relevance of the conserved disulfide bridge and the resulting cyclic structure of both LFcins were analyzed by using “click chemistry” and sortase A-catalyzed cyclization of the peptides. The N-terminal region of bovine LFcin (residues 17–25 of bovine LF) proved to be very important for the antimicrobial activity of the chimera peptides against E. coli, when combined with the C-terminal region of human LFcin. Similarly the cyclic bovine LFcin analogs generated by “click chemistry” and sortase A preserved the antimicrobial activity of the original peptide, showing the significance of these two techniques in the design of cyclic antimicrobial peptides. The mechanism of action of bovine LFcin and its active derived peptides was strongly correlated with membrane leakage in E. coli and up to some extent with the ability to induce vesicle aggregation. This mechanism was also preserved under conditions of high ionic strength (150 mM NaCl) illustrating the importance of these peptides in a more physiologically relevant system. 相似文献
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Comparison of human and humanoid robot control of upright stance 总被引:1,自引:0,他引:1
There is considerable recent interest in developing humanoid robots. An important substrate for many motor actions in both humans and biped robots is the ability to maintain a statically or dynamically stable posture. Given the success of the human design, one would expect there are lessons to be learned in formulating a postural control mechanism for robots. In this study we limit ourselves to considering the problem of maintaining upright stance. Human stance control is compared to a suggested method for robot stance control called zero moment point (ZMP) compensation. Results from experimental and modeling studies suggest there are two important subsystems that account for the low- and mid-frequency (DC to 1 Hz) dynamic characteristics of human stance control. These subsystems are (1) a “sensory integration” mechanism whereby orientation information from multiple sensory systems encoding body kinematics (i.e. position, velocity) is flexibly combined to provide an overall estimate of body orientation while allowing adjustments (sensory re-weighting) that compensate for changing environmental conditions and (2) an “effort control” mechanism that uses kinetic-related (i.e., force-related) sensory information to reduce the mean deviation of body orientation from upright. Functionally, ZMP compensation is directly analogous to how humans appear to use kinetic feedback to modify the main sensory integration feedback loop controlling body orientation. However, a flexible sensory integration mechanism is missing from robot control leaving the robot vulnerable to instability in conditions where humans are able to maintain stance. We suggest the addition of a simple form of sensory integration to improve robot stance control. We also investigate how the biological constraint of feedback time delay influences the human stance control design. The human system may serve as a guide for improved robot control, but should not be directly copied because the constraints on robot and human control are different. 相似文献
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An analysis of virulence and colicinogenicity of 180 cultures of pathogenic Escherichia of different origin has shown that the expressed characters occurred in 40 +/- 49% of strains isolated from people and 28.7 +/- 5.1% of strains isolated from water. The dependence of the studied properties on serogroups of the agents is established. These characters are more often inherent in representatives of the dominating serogroups, which may be a reason of their selective advantage in circulation among people and in water. 相似文献
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Nathan A. Machin 《Molecular biology of the cell》2013,24(13):2073-2075
Leaving science to pursue a career in patent law requires a considerable investment of time and energy, and possibly money, with no guarantee of finding a job or of returning to science should the decision prove infelicitous. Yet the large number of former scientists now practicing patent law shows that it can be done. I provide suggestions for investigating the potential opportunities, costs, risks, and rewards of this career path.The molecular biologist wishing to retool herself or himself as a patent law professional has a number of specific career options to choose from. 相似文献
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Robert Aquaron Fran?ois Delange Pascal Marchal Vincent Lognoné Léon Ninane 《Cellular and molecular biology, including cyto-enzymology》2002,48(5):563-569
The major procedure used to correct iodine deficiency is the universal salt iodization by addition of iodide or iodate to salt with an iodine content varying from 7 to 100 mg/kg of salt depending on the country legislation. As an important fraction of consumers in the world prefers natural products over artificial ones, we investigated the industrial feasibility of naturally iodized salt using seaweed as source of iodine. We report the results of the iodine bioavailability in healthy subjects from two seaweeds: Laminaria hyperborea and Gracilaria verrucosa selected due to their high level in iodine as a mineral or an organic form and low levels of heavy metals. As a control we studied in a normal man the bioavailability of pure mineral iodine such as potassium iodide which was excellent i.e. 96.4% and of pure organic iodine such as monoiodotyrosine which was a little lower i.e. 80.0%. Iodine bioavailability from these two seaweeds was studied in nine normal subjects from Marseille (France) which is an iodine sufficient area based on a median urinary iodine level of 137 microg/day and innine normal subjects from Brussels (Belgium) who present a mild iodine deficiency with a value of 73 microg/day. The iodine bioavailability of Gracilaria verrucosa is better than for Laminaria hyperborea (101% versus 90% in Marseille, t=0.812, NS; 85% versus 61.5% in Brussels, t = 2.486, p = 0.024, S*). The urinary excretion of iodine is lower in Brussels than in Marseille for the same seaweed because part of the iodine is stored in the thyroid (101% versus 85% for Gracilaria verrucosa, t = 1.010, NS; 90% versus 61.5% for Laminaria hyperborea, t = 3.879, p= 0.001, S***). 相似文献
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Nonspecific nitrogen in the nutrition of human beings 总被引:2,自引:0,他引:2
C Kies 《Federation proceedings》1972,31(3):1172-1177
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Chronic toxicity of rare-earth elements on human beings 总被引:3,自引:0,他引:3
Zhang H Feng J Zhu W Liu C Xu S Shao P Wu D Yang W Gu J 《Biological trace element research》2000,73(1):1-17
Blood analyses for rare-earth element (REE)-high background regions in South Jiangxi show that the population averages of
many of the biochemical indices deviate markedly from normal values in the normal region. These deviations are thought to
be caused by prolonged intake of REE through food chains in view of that the toxicity of other harmful metals such as Pb and
Cd can be neglected because of their insignificant amounts in the environment. In comparison with the normal region, blood
biochemical indices abnormal in the REE-high regions are manifested as low total serum protein (TSP), albumin, β-globulin,
glutamic pyruvic transitanase, serium triglycerides, and immunoglobulin, but high cholesterol. These deviations may be related
to the REE concentration and composition of food chains, and are sex dependent. Certain blood indices (such as TSP) of different
age groups in the LREE-high region indicate that the influence of REE on males is a one-way irreversible process, whereas
females show a strong ability of restoration. 相似文献
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American Physiological Society;World Medical Association General Assembly 《American journal of physiology. Cell physiology》2002,282(6):3 p following instructions for authors
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