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.     

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.     

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.     

Interrelated emission and spin–spin relaxation feature mediated by VO+ defects in Gd2O3 nanorods subjected to swift ion impact

We report on the manifestation and interconnected photoluminescence and electron paramagnetic resonance responses in gadolinium oxide (Gd₂O₃) nanorods subjected to 80 MeV carbon ion irradiation. On increasing the irradiation fluence between 1 × 10¹¹ and 3 × 10¹² ions/cm², the emission associated with neutral oxygen vacancies (V_Ox), positioned at ~350 nm, undergoes a steady increase compared to that associated with singly charged vacancies (V_O⁺), located at ~414 nm. The enhancement of spin–spin relaxation time (τ_ss) is ascribed to a substantial changeover from V_O⁺ to V_Ox defects with irradiation, the former being recognized as the major contributor to paramagnetic centres. Interconnected luminescence and spin–spin relaxation could provide insight for making advanced nanophosphors and spin valve elements.     

深度楔状缺损两种修复方法的临床疗效观察

通过光固化氢氧化钙垫底后Dyract复合体修复和直接用Fuji II玻璃离子水门汀分别修复牙颈部深度楔状缺损,临床观察6个月～24个月。对二者的治疗效果进行研究分析,认为玻璃离子水门汀直接修复深度楔状缺损治疗效果优于以光固化氢氧化钙垫底用Dyract复合体修复,Fuji II玻璃离子水门汀直接充填是一种较理想的修复深度楔状缺损技术。     

神经管缺陷的病因、预防与产前控制

神经管缺陷(NTDS)是一种常见的先天性中枢神经系统畸形,其发生率占据我国出生缺陷的前列。本文从其发病原因、产前诊断及预防措施进行系统分析,希望能找出一条降低其发生率的有效途径,从而进一步提高我国的人口素质。     

Offspring Effects of Prenatal Alcohol Exposure from Birth to 25 Years: The Seattle Prospective Longitudinal Study

Before alcohol was generally known to cause birth defects, NIAAA in 1974 began funding a population-based Seattle study on alcohol use and pregnancy outcome. Women receiving prenatal care by mid-pregnancy were recruited (N = 1,529) and interviewed at home. Approximately 500 offspring exposed to a range of alcohol levels were examined on 11 occasions between day 1 and 25 years. Neuropsychological and neurobehavioral performance measures are correlated with prenatal alcohol dose, without substantial confounding by socio-demographic or rearing conditions, smoking, nutrition, or other drugs. Deficits in attention, arithmetic skill, spatial-visual memory, and IQ, as well as increased alcohol problems and psychiatric disorders are among offspring outcomes correlated at several ages with maternal drinking during and before pregnancy recognition. Findings are not confined to women who believed they had alcohol problems. Not all exposed offspring appear affected.     

Canonical Extensions and Relational Representations of Lattices with Negation

This work is part of a wider investigation into lattice-structured algebras and associated dual representations obtained via the methodology of canonical extensions. To this end, here we study lattices, not necessarily distributive, with negation operations.We consider equational classes of lattices equipped with a negation operation ¬ which is dually self-adjoint (the pair (¬,¬) is a Galois connection) and other axioms are added so as to give classes of lattices in which the negation is De Morgan, orthonegation, antilogism, pseudocomplementation or weak pseudocomplementation. These classes are shown to be canonical and dual relational structures are given in a generalized Kripke-style. The fact that the negation is dually self-adjoint plays an important role here, as it implies that it sends arbitrary joins to meets and that will allow us to define the dual structures in a uniform way.Among these classes, all but one—that of lattices with a negation which is an antilogism—were previously studied by W. Dzik, E. Or?owska and C. van Alten using Urquhart duality.In some cases in which a given axiom does not imply that negation is dually self-adjoint, canonicity is proven with the weaker assumption of antitonicity of the negation.