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Key ethical issues arise in association with the conduct of stem cell research by research institutions in the United States. These ethical issues, summarized in detail, receive no adequate translation into federal laws or regulations, also described in this article. U.S. Federal policy takes a passive approach to these ethical issues, translating them simply into limitations on taxpayer funding, and foregoes scientific and ethical leadership while protecting intellectual property interests through a laissez faire approach to stem cell patents and licenses. Those patents and licenses, far from being scientifically and ethically neutral in effect, virtually prohibit commercially sponsored research that could otherwise be a realistic alternative to the federal funding gap. The lack of federal funding and related data-sharing principles, combined with the effect of U.S. patent policy, the lack of key agency guidance, and the proliferation of divergent state laws arising from the lack of Federal leadership, significantly impede ethical stem cell research in the United States, without coherently supporting any consensus ethical vision. Research institutions must themselves implement steps, described in the article, to integrate addressing ethical review with the many legal compliance issues U.S. federal and state laws create. The opinions expressed in this article are the author’s own, and are not necessarily the opinions of others, including Children’s Hospital Boston. Portions of earlier versions of this article were previously published by the American Bar Association and the New York State Bar Association.  相似文献   
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The immunotoxin 192-saporin, infused intracerebroventricularly into rats, destroys cholinergic neurons in the basal forebrain nuclei. Doses required for complete cholinergic loss also kill some Purkinje cells. The immunotoxin OX7-saporin, when infused intraventricularly into rats, destroys Purkinje cells in a pattern similar to that produced by 192-saporin, without affecting cholinergic neurons. Thus, we used OX7-saporin to distinguish behavioral effects of 192-saporin due to cerebellar damage versus those due to cholinergic cell loss. Three doses of 192-saporin (1.6, 2.6, and 3.3 micrograms/rat) were chosen along with a dose of OX7-saporin (2.0 micrograms/rat) that produced Purkinje loss equivalent to the two highest doses of 192-saporin. Groups of Fischer-344 rats were trained in the multiple choice reaction time task and retested with more complex tasks after lesioning. They were also tested in the water maze, passive avoidance, acoustic startle, and open field. The OX7-saporin group exhibited changes in many tests suggesting hypermotility and sensory deficits. The 192-saporin groups differed from the OX7-saporin group when they displayed deficits in multiple choice reaction time tasks in which novel challenges were introduced, including sessions with a noise distractor, shortened and lengthened intertrial intervals, and use of nine instead of five sources of light stimulus. The 192-saporin groups showed no impairment in the other tasks. The cholinergic basal forebrain lesion may mask some of the effects of cerebellar damage up to a threshold after which effects of Purkinje cell loss predominate when 192-saporin is administered intraventricularly.  相似文献   
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随着人们对于肿瘤性疾病的发生、发展、转移机制的进一步探索,循环肿瘤细胞(CTCs)逐渐进入人们视野,其应用价值日益体现,可用于肿瘤性疾病的早期诊断及治疗效果的监测,尤其是对于早期肿瘤的诊断具有独特优势。其富集技术及检测方法也在发生着日新月异的变化。近年来,微流控分析芯片技术运用于 CTCs 的富集及检测,具有高丰度、高富集度、高活性及不需要对样本进行预处理等优点使得人们聚焦于此技术,本文对微流控分析芯片在 CTCs 检测中的运用做简要综述。  相似文献   
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射频消融术(RFA )、肝动脉化疗栓塞术(TACE)及 DC-CIK 治疗等非手术方法已成为治疗小肝癌的重要手段。RFA 及 TACE 直接杀伤肿瘤细胞,DC-CIK 治疗明显改善机体免疫功能。 TACE 联合 RFA 术后序贯 DC-CIK 治疗可取长补短,提高治疗的有效性、安全性及患者的远期疗效。本文主要对 DC-CIK 治疗、TACE 、RFA 治疗现状及联合治疗前景做一综述。  相似文献   
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Parietal cortical areas are involved in sensori-motor transformations for their respective contralateral hemifield/body. When arms of the subjects are crossed while their gaze is fixed straight ahead, vision of the hand is processed by the hemisphere ipsilateral to the arm position and proprioception of the arm by the contralateral hemisphere. It induces interhemispheric transfer and remapping. Our objective was to investigate whether a single pulse TMS applied to the left parietal cortical area would disturb interhemispheric remapping in a similar case, and would increase a simple reaction time (RT) with respect to a control single pulse TMS applied to the frontal cortical area. Two LED were superimposed and located in front of the subjects on the saggital axis. Subjects were asked to carefully fixate on these LED during each trial. The lighting of the red LED was used as a warning signal. Following the green one was illuminated after a variable delay and served as a go-signal. The hand for the response was determined before the start of each trial. TMS was applied to the left parietal, the left frontal cortical areas, or not applied to the subject. Results revealed that: (1) Irrespective of its location, single pulse TMS induced a non-specific effect similar to a startle reflex and reduced RT substantially (15 ms on average) with respect to a control condition without TMS (mean value = 153 ms). (2) Irrespective of TMS, RT were shorter when the right or the left hand was positioned in the right visual hemi-field (i.e. normal and crossed positions respectively). (3) Finally, RT increased when single pulse TMS was applied to the left parietal area and when hands were crossed irrespective of which hand was used. We concluded that interhemispheric sensori-motor remapping was disrupted by a single pulse TMS that was applied to the left parietal cortex. This effect was also combined with some visual attention directed towards the hand located on the right visual hemi-field.  相似文献   
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ABSTRACT

Recently a novel type of epithelial cell has been discovered and dubbed the ‘scutoid’. It is induced by curvature of the bounding surfaces. We show by simulations and experiments that such cells are to be found in a dry foam subjected to this boundary condition.  相似文献   
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Although for many years a sharp distinction has been made in language research between rules and words—with primary interest on rules—this distinction is now blurred in many theories. If anything, the focus of attention has shifted in recent years in favor of words. Results from many different areas of language research suggest that the lexicon is representationally rich, that it is the source of much productive behavior, and that lexically specific information plays a critical and early role in the interpretation of grammatical structure. But how much information can or should be placed in the lexicon? This is the question I address here. I review a set of studies whose results indicate that event knowledge plays a significant role in early stages of sentence processing and structural analysis. This poses a conundrum for traditional views of the lexicon. Either the lexicon must be expanded to include factors that do not plausibly seem to belong there; or else virtually all information about word meaning is removed, leaving the lexicon impoverished. I suggest a third alternative, which provides a way to account for lexical knowledge without a mental lexicon.  相似文献   
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