不应追求“克隆转忆人”的论证是否成立?——答李锐锋、鲁琴的“商榷”

对我以"克隆转忆人"的方式实现人类永生之梦的构想,李锐锋与鲁琴撰文从多个方面进行了批驳,主要涉及如何理解永生、"我之为我"的关键、永生的价值、"克隆转忆人"的生产是否违背自然规律等问题。可经逐一辨析,发觉这些批驳还是与此前已有的各种质疑一样难以成立。

“克隆转忆人”真的当求吗?——兼与韩东屏教授商榷

韩东屏教授试图通过"克隆转忆人"技术,实现"永生不死"的梦想,但"克隆转忆人"即使技术上可为,也未必当求。因为"克隆转忆人"并不是人们追求的此生永在。由于肉体和精神的分裂有可能滑向身心二元论、不断地自我重复移植不仅有可能消解生命的价值和意义,而且还违背了新陈代谢的根本法则。"克隆转忆人"技术的实质是对自然生命的"限定"、"促逼"和"强求",使新生个体处于不自然、非本真状态,有可能给人类带来灾难性后果。

从存在的意义看生命的界限——从“克隆转忆人”之“永生不死”的话题说起

“克隆转忆人”将“永生不死”这个古老的话题赋予了新的意义。“永生不死”表征着人们的生命意识,也为人之所以为人刻画着界限,也是人所独有的“自我意识”。从“生死”之意义域中,似乎可以找到人类文化的某种遗传密码。对“永生不死”之传统意义的超越,就是人“自我意识”之界限的重新划定和意义模式的转型。“永生不死”之可能与否的逻辑与经验仍是理性的自我解释系统的“同一性”要求。“存在”的意义世界为“永生不死”问题的意义确定和意义衍生提供了一个涵括科学并超越科学的视角。

质疑“克隆转忆人”

"克隆转忆人"是克隆人讨论中出现的一个崭新话题。这个话题是由华中科技大学哲学系韩东屏教授作为一个构想提出来的,其基本内涵是:如果克隆人技术和记忆移植技术能够取得成功,那么,利用这两项技术便可以使一个人死而复活,而这样的人就是"克隆转忆人",这样的过程周而复始地进行,就能让人永生不死。问题是这个构想是否能够成立?即便成立,人的永生不死又是否值得追求?以下几篇文章,就是关于这个话题的对话与论辩。

克隆转忆人的利弊分析

克隆转忆人是移植了供体者记忆的克隆人,他使克隆技术对传统伦理道德观念的挑战进一步加剧,克隆人以及克隆转忆人的伦理之争还将继续。

永生是否可能

人能永生不死吗?从人类由古至今的种种探索看,无论是肉体层面的永生不死还是精神层面的永生不死,都未见成功。然而,用克隆转忆的路径就能实现这个梦想。它的基本构思是,在一个人死后,用克隆人技术复制出一个他的肉体,再用记忆移植技术将他的原有记忆转移到这个克隆体的大脑中,就能使他死而复活。而这样的过程不断重复进行,就意味着他的永生不死。

永生不死:可能当求

人能永生不死吗?从人类由古至今的种种探索看,无论是肉体层面的永生不死还是精神层面的永生不死,都未见成功。然而用克隆转忆的路径就能实现这个梦想,它的基本构思是:在一个人死后,用克隆人技术复制出一个他的肉体,再用记忆移植技术将他的原有记忆转移到这个克隆体的大脑中,就能使他死而复活。而这样的过程不断重复进行,就意味着他的永生不死。能做之事,不一定就是当做之事。经过方法论的探讨和利弊分析,这里的结论是:人的永生是值得追求的。

Equal channel angular extrusion of NiTi shape memory alloy tube

As a new attempt, equal channel angular extrusion （ECAE） of nickel-titanium shape memory alloy （NiTi SMA） tube was investigated by means of process experiment, finite element method （FEM） and microscopy. NiTi SMA tube with the steel core in it was inserted into the steel can during ECAE of NiTi SMA tube. Based on rigid-viscoplastic FEM, multiple coupled boundary conditions and multiple constitutive models were used for finite element simulation of ECAE of NiTi SMA tube, where the effective stress field, the effective strain field and the velocity field were obtained. Finite element simulation results are in good accordance with the experimental ones. Finite element simulation results reveal that the velocity field shows the minimum value in the corner of NiTi SMA tube, where severe shear deformation occurs. Microstructural observation results reveal that severe plastic deformation leads to a certain grain orientation as well as occurrence of substructures in the grain interior and dynamic recovery occurs during ECAE of NiTi SMA tube. ECAE of NiTi SMA tube provides a new approach to manufacturing ultrafine-grained NiTi SMA tube.

Influence of recovery heating rate on shape memory effect in up-quenched Cu-Al-Mn alloy

The effect of recovery heating rate on shape memory effect of the up-quenched Cu-8.88Al-10.27Mn（mass fraction, %） alloy was investigated by optical microscopy, electron transmission microscopy（TEM） and electrical resistivity measurement. It is found that the shape recovery rate decreases as the heating rate decreases. It can reach 75% when the heating rate is 20 ℃/min, while it is only 8% when the heating rate is 1 ℃/min. In situ microstructure observation indicates that the dependence of shape memory effect on recovery heating rate is caused by the stabilization of twinned martensite induced by deformation. The analysis of electrical resistivity shows that the stabilization of twinned martensite may be ascribed to formation of compound defects of vacancies and dislocations at the boundaries of twinned martensite during the slow heating. The compound defects prevent the reverse transformation of twinned martensite.

Nonlinear Analysis of Shape Memory Alloy Component in Rotor System

The active control of rotor vibration was studied while shape memory alloy （SMA） spring component was chosen as bearing of rotor system. The vibration of rotor system was controlled by the phase transformation of SMA with electric heating method. The SMA spring component has nonlinear coupling problem of thermal stress and thermal elasticity,because thermal constants α,β and elasticity constants λ,G vary with temperature when temperature changes sharply. Because δ,ε were both small parameters, their square items could be ignored and approximate results were obtained by perturbation. The characters of α,β,λ,G changing with temperature were analyzed. Results show that the character of thermal diffusivity α changes with temperature, which cannot influence U,Ψ,So the nonlinearity of α can be ignored; the character of β changes with temperature, which cannot influence U, but influences Ψ at high temperature; the character of λ,G change with temperature, which cannot influence Ψ, but influences U with U（01） ε. The more λ,G, the more their influence on U; the nonlinearity of βTρcvεkk influences U and Ψ, which must be calculated.

Spatial learning deficits in amyloid precursor protein 770 transgenic mice

Objective To determine whether learning deficits could be seen in transgenic mice expressing human amyloid precursor protein 770 (APP 770 ) Methods Female heterozygous transgenic and nontransgenic mice aged 3, 6 and 9 months at the start of testing were used, with eight mice in each age group All mice were subjected to various behavioral tasks including the Y maze task and the Morris water maze After behavioral testing, the mice were sacrificed, and their brain tissues were used for measuring the choline acetyltransferase (ChAT) activity Results Nine month old transgenic mice exhibited spatial learning deficits in the Morris water maze and in spontaneous alternation in the Y maze, compared with those of the age matched non transgenic mice The behavioral changes accompanied a reduction of ChAT activity in the cortical and hippocampal regions of transgenic mice On the other hand, these behavioral deficits were not observed in transgenic mice either at 3 or at 6 months of age, in which ChAT activity remained unchanged Conclusions The present results show that the learning impairment observed in 9 month old APP 770 transgenic mice are accompanied by a decrease in cortical and hippocampal ChAT activities This suggests that cholinergic deficits may be involved in the learning impairment observed in these APP 770 mice This model will be a useful tool in advancing our understanding of the relationship between the cholinergic system and the cognitive deficits observed in Alzheimer's disease (AD)

Influence of stresses on martensitic transformation in ferromagnetic shape memory Ni_(50)Mn_(19)Fe_6Ga_(25) ribbons

The influence of stresses on martensitic transformation in Ni50Mn19Fe6Ga25 melt-spun ribbons was studied. X-ray diffraction examination shows that the ribbon has a pure cubic L21 phase at room temperature and that the ribbon surface exhibits [100] preferentially oriented texture, while the [110] axis is about 45° tilted from the normal of the ribbon. By calculating the d spacing at different angles with the length direction of the ribbon, the tension was observed. It was found that the direction of the stress was along [010] direction of the oriented textured grains. During cooling, there is no obvious structural transition observed in as-spun ribbons. However, when the ribbons were annealed at 900 K for 24 h, the tension along [010] direction disappeared and the structural transition from cubic to tetragonal occurred obviously during cooling. It indicates that it is the tension along [010] direction to suppress the martensitic transformation in the as-spun ribbons.

Conjugated microporous polymers for near-infrared photothermal control of shape change

Herein,a facile and highly efficient synthetic method to prepare organic photothermal materials with high photo-stability and outstanding photothermal performance is reported.Through direct polymerization of commercial aromatic monomers in the presence of anhydrous aluminium chloride and dichloromethane,four kinds of conjugated microporous polymers(CMPs)were obtained.Detailed structural analysis confirmed that the resultant CMPs possessed abundant micropores with an extendedπ-conjugated skeleton.Under near-infrared(NIR)light irradiation(808 nm,1.0 W cm−2),all the CMPs showed fast heating-up behavior with their maximum temperatures higher than 150℃.Moreover,the efficiency of photothermal conversion(η)of the CMPs was found to increase linearly with the increase in the number of conjugated benzene rings within the monomer.Poly-TPE from tetraphenylethylene(TPE)and Poly-TP from o-terphenyl(TP)showed highηvalues of over 47%.Poly-TPE was additionally used as a photothermal filler to remotely and spatially control the shape recovery of thermal-sensitive shape memory polymers(SMPs),while its introduction(1 wt%)had little influence on the thermal and mechanical properties of the polymer matrixes.Owing to their excellent NIR photothermal performance as well as a one-step synthetic preparation,these CMPs may be promising photothermal materials for practical applications.