A thermodynamic model for nanocrystallization in bulk metallic glasses

The structural complexity of glass-forming alloys, which generally contain more than three components, can lead by partial crystallization during annealing to a dispersion of nanocrystals in an amorphous matrix, giving the material a very high mechanical strength. In the present study, the evolution of the driving force for crystallization is expressed as a function of the composition and the chemical potentials of the components. Application to Zr₆₀Al₁₀Cu₃₀ and Zr₆₀Al₁₀Cu₂₀Pd₁₀ bulk metallic glasses shows that the first crystallization step leads to a metastable equilibrium between nanocrystals of an intermetallic and a percolating amorphous phase. The effects of the number of components and of chemical bonding on the fraction crystallized is analysed and discussed.     

Multiple hydrogen trapping at monovacancies

Novel structures for multiple hydrogen atoms trapped at a monovacancy are discussed. Using atomistic simulations based on semiempirical interatomic potentials and density functional theory, we find low-energy configurations for four, five, and six hydrogen atoms around a monovacancy different than those that have been previously studied in the literature. The energetics of hydrogen binding are compared to results, both theoretical and experimental, previously published in the literature. We argue that up to four hydrogen atoms may be exothermically bound to monovacancy.     

Destructiveness, atrocities and healing: epistemological and clinical reflections

In this paper, destructiveness is approached as a multi-dimensional phenomenon where the mental health perspective addresses only one of these dimensions. An attempt is made to locate this phenomenon in the context of epistemological and societal considerations. Critical of mono-dimensional explanations based on causal-reductive epistemology, the paper instead proposes the idea of an 'ecology of destructiveness', according to which mental health professionals cannot possibly continue to assume the role of detached observers. The ordinariness and archetypal fascination of destructiveness are discussed as preventing the psychologizing and pathologizing of it. In addition, it is suggested that 'destructiveness may be a tragic facet of the human condition', without this implying any justification of it. Based on my work with a group of Bosnian ex-camp prisoners, some basic principles of how one can work with survivors of atrocities are derived and discussed. A central feature of this work is the attempt to create an appropriate therapeutic context within which a 'therapeutic presence' and 'therapeutic witnessing' can be developed. Finally, the relevance of Jungian insights to this kind of work is reviewed and the emergence of new types of defences of the self is identified.     

电子媒体使用对睡眠的影响,机制及其干预

电子媒体设备日益流行的同时, 睡眠问题也日趋加重, 主客观研究均发现电子媒体使用会对睡眠产生消极影响.背后的加工机制涉及睡眠置换,唤醒,屏幕光和电磁辐射.可以通过睡眠卫生教育,限制电子媒体使用,屏蔽屏幕蓝光等方式进行干预.未来研究需要从理论机制的整合,因果关系的确定,测量方式的客观化和标准化,使用情况细化和本土化研究方面做努力.     

小儿放射检查的麻醉方法及安全性探讨

探讨用于小儿放射检查的安全、有效的麻醉方法。选择60例1岁～8岁ASAⅠ-Ⅱ级小儿,分别采用单纯氯胺酮、咪达唑仑复合氯胺酮和异丙酚复合氯胺酮3种麻醉方法。观察3种麻醉方法的效果和安全性以及不良反应,辩证地分析3种麻醉方法的优缺点,思考小儿放射检查的合适的麻醉方法。     

调强适形放射治疗的多学科整合

调强适形放射治疗是放射治疗100余年历史中的一个革命性进步,能使高剂量的立体分布适合外形非常不规则甚至怪异的肿瘤,调整靶区内诸点的输出剂量率,显著提高肿瘤放疗的疗效。近年计算机技术、放射物理学、放射生物学、分子生物学、影像学特别是功能性影像学的快速发展以及多门边缘学科之间的有机结合,为调强适形放射治疗提供在靶区三维精确模拟定位、立体定向定位摆位框架、逆向治疗计划系统、调强治疗机等方面的发展基础。调强适形放射治疗——多元化医学理论下的医疗方法将在学科交叉、综合发展中进一步巩固。     

Neuroticism and responses to social comparison among cancer patients

The present study examined how the effects of three audiotapes containing different types of social comparison information on the mood of cancer patients depended on the level of neuroticism. On the procedural tape, a man and woman discussed the process of radiation therapy, on the emotion tape, they focussed on emotional reactions to their illness and treatment, while on the coping tape they focussed on the way they had been coping. A validation study among 115 students showed that the tapes were perceived as they were intended. The main study was conducted among 226 patients who were about to undergo radiation therapy. Compared to patients in the control group, as patients were higher in neuroticism, they reported less negative mood after listening to the procedural and the coping tape. Furthermore, as patients were higher in neuroticism, they reported less negative mood after listening to the coping tape than to the emotion tape. Copyright © 2009 John Wiley & Sons, Ltd.     

涎腺肌上皮癌诊治发展的研究

涎腺肌上皮癌是一种发生于涎腺的罕见恶性肿瘤,随着研究的深入,对其生物学行为及治疗争议较大,其中牵涉到很多矛盾的思想观点,如涎腺肌上皮癌的恶性程度与分型,诊断,颈淋巴清扫的选择,术后辅助放化疗的选择等。本文对其中所蕴涵的哲学思想进行反思,以期引导对涎腺肌上皮癌的科学认识。     

核辐射对消化系统损害的防治策略

消化系统中多个器官具有细胞代谢快、易受核射线损伤的特点,成为骨髓以外最容易遭受核辐射破坏的身体部位。日本核电站的泄露事故,使核辐射再度成为世界的焦点。随着人们对电离辐射认识的增加,核辐射对消化系统的损害也逐渐受到重视。本文通过对消化系统的损害机制的研究,论述了核辐射对消化系统的损害的防护和治疗策略。     

Specifying factors in radiation risk perception

This is a study of risk perception and a test of a model of perceived risk. A scale measuring fear was factor analyzed and the resulting five fear factors were related to a large number of risk dimensions, both personal and general. Fear was only rather weakly related to perceived risk. Furthermore, perceived risk of two ionizing radiation hazards (nuclear power, X-rays) were investigated in more detail. These risk ratings were modelled on the basis of attitude, risk sensitivity, specific perceived risk of radiation, trust and an extended version of the traditional Psychometric Model, enhanced by the introduction of a factor of Tampering with Nature. It was found that risk perception could be well explained with this approach and the importance of Tampering with Nature, as well as specific perceived risk, were stressed.