Molecularly imprinted polymers as the extracted sorbents of clenbuterol ahead of liquid chromatographic determination

A pre-treatment methodology for clenbuterol hydrochloride (CLEN) isolation and enrichment in a complex matrix environment was developed through exploiting molecularly imprinted polymers (MIPs). CLEN-imprinted polymers were synthesized by the combined use of ally-β-cyclodextrin (ally-β-CD) and methacrylic acid (MAA), allyl-β-CD and acrylonitrile (AN), and allyl-β-CD and methyl methacrylate (MMA) as the binary functional monomers. MAA-linked allyl-β-CD MIPs (M-MAA) were characterized by Fourier transform-infrared (FT-IR) spectroscopy and a scanning electron microscope (SEM). Based upon the results, M-MAA polymers generally proved to be an excellent selective extraction compared to its references: AN-linked allyl-β-CD MIPs (M-AN) and MMA-linked allyl-β-CD MIPs (M-MMA). M-MAA polymers were eventually chosen to run through a molecularly imprinted solid-phase extraction (MISPE) micro-column to enrich CLEN residues spiked in pig livers. A high recovery was achieved, ranging from 91.03% to 96.76% with relative standard deviation (RSD) ≤4.45%.     

一种增强移动自组网Internet连接的改进型方案

针对移动自组网因单向链路以及盲目转播网关发现分组而造成的与Internet互联性能下降,提出了一种增强型互联方案.同时结合了先应和后应网关发现策略优点的混合网关发现策略被用来获取良好的Internet连接并保持低开销.而通过交换携带有额外增加的对称邻居节点列表和非对称邻居节点列表字段的AODV hello分组,单向链路得以从路由计算中予以清除而广播风暴也同时得到抑制.基于ns-2的仿真结果表明此改进型Internet连接方案在单向链路数量及节点移动速度均变化的应用环境下能取得较其他方案为优的互联性能.     

Assessment of three-dimensional joint kinematics of the upper limb during simulated swimming using wearable inertial-magnetic measurement units

The analysis of the joint kinematics during swimming plays a fundamental role both in sports conditioning and in clinical contexts. Contrary to the traditional video analysis, wearable inertial-magnetic measurements units (IMMUs) allow to analyse both the underwater and aerial phases of the swimming stroke over the whole length of the swimming pool. Furthermore, the rapid calibration and short data processing required by IMMUs provide coaches and athletes with an immediate feedback on swimming kinematics during training. This study aimed to develop a protocol to assess the three-dimensional kinematics of the upper limbs during swimming using IMMUs. Kinematics were evaluated during simulated dry-land swimming trials performed in the laboratory by eight swimmers. A stereo-photogrammetric system was used as the gold standard. The results showed high coefficient of multiple correlation (CMC) values, with median (first–third quartile) of 0.97 (0.93–0.95) and 0.99 (0.97–0.99) for simulated front-crawl and breaststroke, respectively. Furthermore, the joint angles were estimated with an accuracy increasing from distal to proximal joints, with wrist indices showing median CMC values always higher than 0.90. The present findings represent an important step towards the practical use of technology based on IMMUs for the kinematic analysis of swimming in applied contexts.     

Effects of tapering on physical match activities in professional soccer players

ABSTRACT

This study aimed to examine: (i) the effect of decreasing training load (TL) during taper weeks on physical match activities in professional soccer players, and (ii) to disclose the relationship between weekly TL and physical match activities. Rating of perceived exertion was collected after each training session and match to quantify the TL in 19 professional players over 17 standard and 7 taper weeks during the season. Physical match activities were quantified by a computerised match analysis system and compared between standard training and taper weeks. Compared to standard weeks, the duration and frequency of training sessions during the taper weeks decreased (?21.7% and ?18.8%, respectively; P < 0.01) with no change in intensity (?4.8%; P = 0.09). Consequently, the weekly TL decreased during the taper weeks (?25.5%; P < 0.01). Increases in distance covered by intense running (+15.1%; P < 0.05), high-intensity running (HIR) (+15.7%; P < 0.01), number of sprints (+17.8%; P < 0.05) and number of high-speed runs (+15.7%; P < 0.05) were observed during the seven matches played after the taper weeks. High relationships were observed between TL and HIR distance covered, number of HIR and number of sprints (r = ?0.53; r = ?0.55; r = ?0.65, respectively; P < 0.01). Decreasing TL during taper weeks by reducing training duration and frequency but maintaining intensity was associated with an increase in physical activities during matches. However, it needs to be determined whether tapering or other match factors led to the changes in match activity.     

黑龙江省冰雪装备制造业创新成长影响要素与战略研究

随着我国成功申办2022年冬奥会,我国将大力发展冰雪运动,并会随之带动旅游、经济和冰雪装备制造业的发展。而冰雪装备制造业的发展直接影响我国冰雪体育事业的开展。采用文献资料、调查、系统分析等研究方法,针对黑龙江省冰雪装备制造业的创新成长问题进行研究,并对黑龙江省的冰雪装备制造业创新成长影响要素以及企业创新成长存在的问题进行分析与总结,认为黑龙江省冰雪装备制造业创新成长的总体状况是良好的,但企业存在资金短缺,经营、管理、技术等方面人才匮乏,企业产品结构单一、产品科技创新意识和能力不强,欠缺可持续发展理念等问题。通过分析影响冰雪装备制造业创新成长的原因,提出引进与自我创新相结合、注重品牌质量、发扬政府主导优势等战略,旨为冰雪装备制造业在黑龙江省的发展提供理论依据。     

时代的热言——论《南方都市报》的新闻评论

《南方都市报》高度重视新闻评论,不但天天有社论,而且用两个版面刊发新闻评论,强化新闻评论与公众的需求和愿望的紧密联系,及时褒贬现实,评论公众关注和社会形成的热点蕴含的因素,满足公众和社会的需要,具有很高的新闻评论价值,极大地提升了《南方都市报》的品位和品牌。《南方都市报》的新闻评论还追求高端性与精英性的结合,刊发精英作者撰写的新闻评论,选取与公众利益密切相关的论题进行评论,显示出鲜明的广泛性和开放性的精英倾向,与流行的“公民写作”保持距离,代表着《南方都市报》追求高品位的旗帜。     

基于Pro/E的直齿锥齿轮Program参数化造型

介绍Pro/Engineer的Program参数化造型方法及其程序结构,并且以直齿锥齿轮为实例,详细地介绍Program参数化造型的实现过程。为同类产品实现参数化造型,减少重复劳动,提高设计效率提供一种适用、有效的方法。     

日本环境教育探析

日本在发展经济的过程中非常重视环境教育，其基本着眼点是：通过对传统文化的挖掘和诠释，搭建起环境教育的价值支持系统；通过政府、企业、社区、NGO组织(Non-governmental organization，非政府组织)的共同努力、协同配合，构造出完整的环境教育体系；通过公害教育使社会民众始终保持对环境问题的敏感性。这些做法可以为我国的环境教育提供重要的启示和参照。     

学习者行为追踪系统的架构与实现

学习者行为追踪是对学习者与网络平台之间的互动过程进行数据采集、数据处理和数据分析的技术。行为追踪可用于了解网络学习的过程,行为追踪系统是其技术实现,它与网络学习平台配合使用。本文介绍了行为追踪系统的架构及实现,着重介绍了系统的三个组成模块及部分关键技术。     

浅析美国大学研究生科研训练的特色

科学研究是研究生培养的重要手段之一。美国大学成功地运用科研训练培育了一大批高素质人才,强大的政府资金支持、严格的指导监督、训练途径的多样化等形成了美国大学研究生科研训练的特色。