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101.
Two complementary debates of the turn of the nineteenth and twentieth century are examined here: the debate on the legitimacy of hypotheses in the natural sciences and the debate on intentionality and ‘representations without object’ in philosophy. Both are shown to rest on two core issues: the attitude of the subject and the mode of presentation chosen to display a domain of phenomena. An orientation other than the one which contributed to shape twentieth-century philosophy of science is explored through the analysis of the role given to assumptions in Boltzmann’s research strategy, where assumptions are contrasted to hypotheses, axioms, and principles, and in Meinong’s criticism of the privileged status attributed to representations in mental activities. Boltzmann’s computational style in mathematics and Meinong’s criticism of the confusion between representation and judgment give prominence to an indirect mode of presentation, adopted in a state of suspended belief which is characteristic of assumptions and which enables one to grasp objects that cannot be reached through direct representation or even analogies. The discussion shows how assumptions and the movement to fiction can be essential steps in the quest for objectivity. The conclusion restates the issues of the two debates in a contemporary perspective and shows how recent developments in philosophy of science and philosophy of language and mind can be brought together by arguing for a twofold conception of reference.  相似文献   
102.
Neuropathic pain is a very complex disease, involving several molecular pathways. Current available drugs are usually not acting on the several mechanisms underlying the generation and propagation of pain. We used spared nerve injury model of neuropathic pain to assess the possible use of human mesenchymal stem cells (hMSCs) as anti-neuropathic tool. Human MSCs were transplanted in the mouse lateral cerebral ventricle. Stem cells injection was performed 4 days after sciatic nerve surgery. Neuropathic mice were monitored 7, 10, 14, 17, and 21 days after surgery. hMSCs were able to reduce pain-like behaviors, such as mechanical allodynia and thermal hyperalgesia, once transplanted in cerebral ventricle. Anti-nociceptive effect was detectable from day 10 after surgery (6 days post cell injection). Human MSCs reduced the mRNA levels of the pro-inflammatory interleukin IL-1β mouse gene, as well as the neural β-galactosidase over-activation in prefrontal cortex of SNI mice. Transplanted hMSCs were able to reduce astrocytic and microglial cell activation.  相似文献   
103.
In the present study we demonstrated that neurotoxin MPP+-induced DNA damage is followed by ataxia telangiectasia muted (ATM) activation either in cerebellar granule cells (CGC) or in B65 cell line. In CGC, the selective ATM inhibitor KU-55933 showed neuroprotective effects against MPP+-induced neuronal cell loss and apoptosis, lending support to the key role of ATM in experimental models of Parkinson’s disease. Likewise, we showed that knockdown of ATM levels in neuroblastoma B65 cells using an ATM-specific siRNA attenuates the phosphorylation of retinoblastoma protein without affecting other cell-cycle proteins involved in the G0/G1 cell-cycle phase. Moreover, we demonstrated DNA damage, in human brain samples of PD patients. These findings support a model in which MPP+ leads to ATM activation with a subsequent DNA damage response and activation of pRb. Therefore, this study demonstrates a new link between DNA damage by MPP+ and cell-cycle re-entry through retinoblastoma protein phosphorylation.  相似文献   
104.
 利用Buch的方法构造出了一类处处连续,但处处不可微函数,该函数是Buch所构造出的函数的推广,并对该函数图像的盒(Bouligand)维数进行了估计,得出了Buch函数的盒维数只是其中的一种特殊情况.  相似文献   
105.
The Amazon basin in transition   总被引:7,自引:0,他引:7  
Agricultural expansion and climate variability have become important agents of disturbance in the Amazon basin. Recent studies have demonstrated considerable resilience of Amazonian forests to moderate annual drought, but they also show that interactions between deforestation, fire and drought potentially lead to losses of carbon storage and changes in regional precipitation patterns and river discharge. Although the basin-wide impacts of land use and drought may not yet surpass the magnitude of natural variability of hydrologic and biogeochemical cycles, there are some signs of a transition to a disturbance-dominated regime. These signs include changing energy and water cycles in the southern and eastern portions of the Amazon basin.  相似文献   
106.
对崩解剂羧甲基淀粉(CMS)固相合成方法进行了研究,筛选了固相合成CMS用催化剂,合成了医药用崩解剂羧甲基淀粉,考察了碱和一氯乙酸用量对CMS取供度(DS)的影响及DS和CMS中游离羧基和成盐羧基比(H/Na)对崩解剂吸水溶胀性能的影响。实验表明,该合成方法与溶液相比,节约了有机溶剂,降低了生产成本,提高了产品质量和收率。  相似文献   
107.
研究了含亮铅锌矿经沸腾炉焙烧的挥发氧化物酸浸处理的浸渣的锌、铅分离,使用添加剂LHY后,常压下用硫酸浸取,在实验条件下,锌的浸取率达98%以上,而铅仍以硫酸铅的形式留在浸渣中,从而有效地将锌、铅分离,而其中稀有元素铟的浸出率也较高。  相似文献   
108.
重组葡激酶(r-Sak)工程菌发酵工艺的研究   总被引:2,自引:0,他引:2  
通过对影响重组葡激酶表达的几个主要因素的研究,建立了较为适宜的发酵条件:接种量4%;初始pH7.2;在A600nm=2.5时加20%蔗糖诱导,诱导后4~5h收获,发酵液上清r-Sak含量可达到250mg/L以上,酶活力可达到6500RU/ml以上。  相似文献   
109.
论述9至13世纪苏非主义在中亚形成和发展,阐述这一时期中亚苏非的主要思想及其与孙派信仰调和的过程以及苏非的精神功修,探讨了中亚苏非由松散的小团体演变成有严格规章制度的教团的三种宗教因素。  相似文献   
110.
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