Folic acid and the prevention of neural tube defects: A position paper of the national society of genetic counselors

Considerable scientific evidence demonstrates the reduction in risk for neural tube defects (NTDs) associated with maternal preconceptional folic acid supplementation. The National Society of Genetic Counselors (NSGC) endorses the U.S. Public Health Service recommendations for folic acid supplementation at the 0.4 mg level for women in the general population and at the 4.0 mg level for women at high or increased risk for NTD pregnancies for at least 4 weeks prior to active pursuit of conception. We encourage targeted educational efforts and surveillance to assess results of this dietary supplementation. The NSGC further urges the Food and Drug Administration to fortify staple foodstuffs with folic acid for a population-based approach to minimize the number of NTD births.     

“重”“错”之义与六十四卦的生成

六十四卦如何由八卦重叠而成,思想家们给出了不同的说法。本文立足“重”与“错”的同异,探讨其成卦的内在机制及其与天地万物变化的联系。孔颖达以相错解释相重,在忽略二者矛盾的前提下进行推论。邵雍立足一分为二发明相错,”重”在他是指天圆地方的天道运动,而与重卦无关。以为邵雍言先天方位的八卦相错是讲重卦的观点缺乏根据。胡宏从太极——天道的运动说明八卦与六十四卦的关系。利用“重道”去解释“重卦”,揭示了六十四卦生成的不同机理。朱熹在总结前人的基础上,按照太极生万物模式的需要发挥邵雍的理论,反映了邵雍以后易学的发展。来知德批评了邵雍、朱熹对相错与相重的混淆,但又不是胡宏的一“重”到底．而是重与错双方相互补充发明,合力生成六十四卦。尽管哲学家们对”重”与“错”的方法的把握和定位不尽相同,但易卦的生成应当是天道运动规律的概括和表现则是他们的基本的共识。     

适合汉语全拼输入的提示性软键盘的研发与验证

本研究设计了两种基于汉语全拼输入的提示性软键盘:加粗加黑和颜色提示,并通过实证性研究验证了这两种提示性软键盘对汉字输入绩效的影响。结果表明,两种提示性软键盘均优于非提示性软键盘,在打字速度、使用方便程度、喜爱程度和总体评价上均更好,加粗加黑提示性软键盘还显著提升了输入正确率。该结果为基于汉字输入的提示性软键盘的研发和使用提供了科学依据和数据支持,也将为相关键盘的投入市场做出贡献。     

A pseudo-binary interdiffusion study in the β-Ni(Pt)Al phase

Interdiffusion study is conducted in the Ni-rich part of the β-Ni(Pt)Al phase following the pseudo-binary approach. Interdiffusion coefficients over the whole composition range considered in this study increases with increase in Pt content, which is in line with the theoretical study predicting the decrease in vacancy formation and migration energy because of Pt addition. The trend of change in diffusion coefficient with the increase in Ni and Pt contents indicates that Pt preferably replaces Ni antisites.     

Four-phonon model of soft-matter quasicrystals for studying thermodynamics

Four-phonon model of soft-matter quasicrystals is proposed, in which there are three solid phonons and one fluid phonon. With this model, the vibration spectrum of soft-matter quasicrystals can be obtained. The generalized Debye frequency, generalized Debye temperature and the thermodynamic functions of soft-matter quasicrystals are observed. The results on the specific heat of soft-matter quasicrystals demonstrate the contributions of both solid phonons and fluid phonon, respectively.     

家庭成员间活体器官及组织捐赠的伦理问题

家庭成员间活体器官及组织捐赠是被绝大多数国家所允许的.虽然利益化减少了很多,但是目前发现其也存在许多的伦理问题.就家庭成员间活体器官及组织捐赠的伦理基础,以及就捐赠风险、种族差异、失衡之爱、操纵、拒绝、退出、潜在利益、特殊疾病等涉及的相关伦理问题进行综述,并就存在的相关问题的解决方法进行探讨.     

Tilted InSb nanostructures fabricated by off-normal ion beam irradiation

ABSTRACT

Using a two-step focused ion beam irradiation process, tilted InSb nanostructures have been fabricated using a off-normal angle of irradiation. In the first step, a well-focused ion beam was used to irradiate the surface of the structure to achieve top-down sputtering. In the second step, the ion beam was used to irradiate the entire surface to promote bottom-up nanostructure growth through the migration of ion-beam-induced interstitial atoms. The formation of a nanostructure with a 46° tilt and an aspect ratio of 0.5 was achieved using ion beam irradiation at an angle of 45° in both steps of the process. The 2% concentration of point defects obtained by changing the volume of the nanostructure before and after irradiation contributed to the growth of the structure. The results showed that many point defects did not recombine, and survived to contribute toward the growth of the wall structure.     

Secondary ageing in Al-Cu-Mg

Secondary ageing, that is microstructural evolution occurring at room temperature after short heating at temperatures above the metastable phase boundary of Guinier-Preston zones, has been studied for an Al-Cu-Mg alloy with a high Cu-to-Mg ratio. Combined data from positron annihilation spectroscopy, Vickers microhardness measurements and differential scanning calorimetry show that, on secondary ageing after 5 or 7min at 190°C, firstly, hardening takes place at a rate nine to 16 times slower than natural age hardening; secondly, vacancies slowly released by Cu-rich aggregates formed during the heat treatment at 190°C promote further formation of solute aggregates, with a time-dependent chemical composition; thirdly, the thermal stability of the structures formed during secondary ageing increases with increasing dwell time at room temperature; and, fourthly, solute aggregates formed at 190°C undergo a structural reorganization and possibly a change in the composition, leading to species with a different thermal stability. The slow release of vacancies from Cu-rich aggregates is proposed as one of the limiting factors of the hardening rate.     

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.