The Prevalence of Childhood Dysphonia: A Cross-Sectional Study

There is only very limited information on the prevalence of voice disorders, particularly for the pediatric population. This study examined the prevalence of dysphonia in a large cohort of children (n = 7389) at 8 years of age. Data were collected within a large prospective epidemiological study and included a formal assessment by one of five research speech and language therapists as well as a parental report of their child's voice. Common risk factors that were also analyzed included sex, sibling numbers, asthma, regular conductive hearing loss, and frequent upper respiratory infection. The research clinicians identified a dysphonia prevalence of 6% compared with a parental report of 11%. Both measures suggested a significant risk of dysphonia for children with older siblings. Other measures were not in agreement between clinician and parental reports. The clinician judgments also suggested significant risk factors for sex (male) but not for any common respiratory or otolaryngological conditions that were analyzed. Parental report suggested significant risk factors with respect to asthma and tonsillectomy. These results are discussed in detail.     

Positron annihilation spectroscopy in tomorrow's material defect studies

Positron Annihilation Spectroscopy (PAS), sometimes refered to as Positron Annihilation Lifetime Spectroscopy (PALS), are non-destructive techniques commonly used for defects and voids study in materials. It provides a handy tool for in-depth profiling down to few microns, and in determining open volume defects like dislocation, agglomerates, and vacancies at ppm concentration. PAS with the aid of Doppler broadening has certainly opened a new gateway in the spectroscopy of solid state physics, metals, RO systems, and semiconductors. Since it is an antiparticle of the electron it gives better information on the electron density in the material of interest. The lifetime of a positron is a complex function of electron density present at the annihilation site. To add beauty, in principle PAS gives the type and concentration of the defect independently by a single measurement. This article presents PAS based on the most relevant, most iconic, and most recent references.     

Comparison of [18F]F-CNBI and [18F]F-CNPIFE as Positron Emission Tomography Probes for Noninvasive Imaging of Glycogen Synthase Kinase-3 in Normal Mice

Glycogen synthase kinase-3 α/β is involved in dysregulation of neuronal tau protein in Alzheimer's disease (AD). There is an unmet clinical need for a blood-brain barrier (BBB) permeable positron emission tomography (PET) probe for imaging of GSK-3α/β in the brain to understand the pathogenesis of AD. Herein, we synthesized two PET probes, [¹⁸F]F-CNBI and [¹⁸F]F-CNPIFE, and evaluated their BBB permeability and affinity towards GSK-3α/β. [¹⁹F]F-CNPIFE showed higher in-vitro binding towards GSK-3α/β (IC₅₀=19.4±2.5 nM; n=3, for GSK-3α, IC₅₀=19.4±3.8 nM; n=3, for GSK-3β) compared to [¹⁹F]F-CNBI (IC₅₀=107.6±26.0 nM; n=4, for GSK-3α, IC₅₀=105.3±18.2 nM; n=3, for GSK-3β). [¹⁸F]F-CNPIFE showed 9.5-fold higher brain uptake than [¹⁸F]F-CNBI, in normal FVB/NJ mice, which was increased by additional 1.5-fold on co-administration of [¹⁹F]F-CNPIFE with respect to [¹⁸F]F-CNBI. Overall, [¹⁸F]F-CNPIFE is a promising PET probe for GSK-3α/β imaging and warrants further evaluation in an AD mouse model.     

Modification of single walled carbon nanotube surface chemistry to improve aqueous solubility and enhance cellular interactions

Single walled carbon nanotubes (SWNTs) continue to demonstrate the potential of nanoscaled materials in a wide range of applications. The ability to modulate the mechanical or electrical properties of a material by varying the SWNT component may result in diverse "application tunable" materials. Similarly, biomaterials used in tissue engineering applications may benefit from these characteristics by varying electrical and mechanical properties to enhance or direct tissue specific regeneration. The interactions between SWNTs and cellular systems need to be optimized to integrate these highly hydrophobic nanoparticles within an aqueous environment while maintaining their unique properties. We assessed solubility, conductance, and cellular interactions between four different SWNT preparations (unrefined, refined, and SWNT with either albumin or human plasma adsorbed). Initial interactions between cells and SWNTs were assessed within a 3D environment using a red blood cell lysis model, with longer-term interactions assessing the effects on PC12 and 3T3 fibroblast function when cultured on SWNT-collagen composite hydrogels. After SWNT purification, the lytic effect on red blood cells (RBCs) is significantly reduced from 11% to 0.7%, indicating manufacturing contaminants play a significant role in undesirable cell interactions. Nanotubes with either human plasma or albumin physisorbed onto the nanotube surface were significantly more hydrophilic than either unrefined or refined preparations and displayed improved RBC interactions. Despite improved dispersion, purification, and adsorption of either plasma or albumin, SWNTs caused a significant reduction in conductance. Although the molecular interactions occurring at the cell membrane remain unclear, these investigations have identified two main factors contributing to membrane failure: manufacturing impurities and to a lesser extend the material's innate hydrophobicity. Although purification is a critical step to remove toxic manufacturing contaminants, care must be taken to ensure improved aqueous dispersion does not compromise desirable mechanical and electrical attributes.     

Enhancement of the stabilization efficiency of a neoclassical magnetic island by modulated electron cyclotron current drive in the ASDEX upgrade tokamak

The efficiency of generating a helical current in magnetic islands for the purpose of suppression of neoclassical tearing modes (NTMs) by electron cyclotron current drive (ECCD) is studied experimentally in the ASDEX Upgrade tokamak. It is found that the efficiency of generating helical current by continuous current drive in a rotating island drops drastically as the width 2d of the co-ECCD driven current becomes larger than the island width W. However, by modulating the co-ECCD in phase with the rotating islands O point, the efficiency can be recovered. The results are in good agreement with theoretical calculations taking into account the equilibration of the externally driven current on the island flux surfaces. The result is especially important for large next-step fusion devices, such as ITER, where 2d>W is expected to be unavoidable during NTM suppression, suggesting that modulation capability should be foreseen.     

300MVA 脉冲发电机高压变频器调速装置设计及调试

HL-2M 装置 300MVA 脉冲发电机组的调速装置高压变频器主要由输入和输出部分、功率单元、控 制部分组成。对高压变频器进行了调试及试验运行。试验表明其输入谐波含量小,输出波形也是完美正弦波,启 动到工作转速的时间为 16min,再加速时间未超过 5min,能够满足实验放电要求。根据调试情况对空载电流及转 子时间常数进行了优化,在空载电流为 300A、转子时间常数为 1.34s 时,其性能为最优。     

HL-2M 装置主机集成安装工程质量管理

基于 HL-2M 装置主机集成安装实践,以风险控制、过程管理为质量管理工作总体思路,对工程策 划、实施、验收环节进行全面质量管理。通过实施质量管理活动,确保了 HL-2M 装置主机集成安装工程达到质 量目标,并于 2020 年 12 月 4 日首次放电成功。通过本项目的实施积累了大科学工程的质量管理经验。     

HL-2M 装置集成安装进度控制研究

大型托卡马克装置集成安装工程子项多、接口繁多、工作空间狭小、系统复杂、参与人员众多,如 何做好装置集成安装的进度控制至关重要。基于工程进度风险管理思维,详细分析了 HL-2M 装置集成安装进度 控制风险因素,并探索了进度控制体系有效运行方式,为安装进度风险可控且实现进度控制目标提供了保障,也 为我国大型磁约束核聚变装置集成安装标准化和规模化发展积累了经验。     

HL-2M 装置极向场线圈的结构设计与制造

介绍了 HL-2M 装置极向场(PF)线圈的结构设计和制造。16 饼 PF 线圈布置在环向场(TF)线圈空腔之 内、真空室外,沿中平面对称分布。PF 线圈采用中空矩形铜导体绕制,其中 PF1~PF4 线圈为双层螺旋绕制结构, 最大运行电流 14.5kA;PF5~PF8 线圈为多层盘式绕制结构,最大运行电流 38~42kA。