Iron determination after on-line sorbent preconcentration by fi-fass using 1, 10-phenanthroline as a complexing agent

1, 10-Phenanthroline (phen) was tested as a complexing agent for on-line preconcentration of iron on RP-C₁₈ material in a microcolumn with flow injection coupled with flame atomic absorption spectrometer (FI-FAAS). The on-line formed Fe(II)-phen complexes were adsorbed on the C₁₈ sorbent material. Various parameters affecting the on-line Fe(II)-phen complex formation and its subsequent adsorption in the microcolumn as well as its elution into the nebulizer of AAS were optimized. A 2.5×10⁻³ mol/L phen in 2% through the microcolumn for 30 s. The adsorbed Fe(II)-phen complexes in the microcolumn were eluted with ethanol in 10 s into the nebulizer of AAS. Ascorbic acid (5×10⁻⁴ mol/L) was added to the sample solution for the reduction of Fe(III) to Fe(II). A good precision (RSD=1.1%,n=10), high enrichment factor (19) and sample throughput (90 h⁻¹) with detection limit (3σ) of 3 μg/L were obtained. The method was applied on standard reference materials (i. e. mussel and tomato leaves,) for iron determination and yielded results agreeing well with certified values. Project supported by the Zhejiang Provincial Natural Science Foundation of China and Zhejiang Environmental Protection Foundation From Pakistan Institute of Nuclear Science & Technology, Islamabad, Pakistan and now ZJ University, Ph. D. student.     

Impact of online social capital on academic performance: exploring the mediating role of online knowledge sharing

Education and Information Technologies - Given the importance of digital communication during the COVID-19 pandemic, the need for advancing academic goals through online social capital is more...     

利用EFQM业务卓越模型重新评估帕亚米·努尔大学中心组织

作为高等教育网络学习中心的帕亚米·努尔大学应该采取措施来建立质量管理系统.并且改革或改变教育服务的机构.在2005～2006年帕亚米·努尔大学中心组织使用EFQM模型作了自我评估,目的是为了建立质量管理系统.为了重新评估该组织,为了通过比较连续两年的成绩来监控该组织发挥作用的效果、为了检测去年进行的第一次试验结果的不足的改进程度,我们又进行了第二次试验,题目相同,试验方法稍作更改.试验的主要目的是为了重新评估该组织通过使用EFQM模型后如何提高了自己的作用并比较这两次试验的结果.本实验除了进行文献搜索以外,还进行了实地调查.     

Review:On dendritic cell-based therapy for cancers

Dendritic cells(DCs),the most prevalent antigen-presenting cell in vivo,had been widely characterized in the lastthree decades.DCs are present in almost all tissues of the body and play cardinal roles in recognition of microbial agents,autoantigens,allergens and alloantigen.DCs process the microbial agents or their antigens and migrate to lymphoid tissues topresent the antigenic peptide to lymphocytes.This leads to activation of antigen-specific lymphocytes.Initially,it was assumedthat DCs are principally involved in the induction and maintenance of adaptive immune responses,but now it is evident that DCsalso have important roles in innate immunity.These features make DCs very good candidates for therapy against variouspathological conditions including malignancies.Initially,DC-based therapy was used in animal models of cancers.Data fromthese studies inspired considerable optimism and DC-based therapies was started in human cancers 8 years ago.In general,DC-based therapy has been found to be safe in pati     

Robust FOPID stabilization of retarded type fractional order plants with interval uncertainties and interval time delay

This study investigates the robust stability of the retarded type of interval fractional order plants with an interval time delay. To this end, the characteristic quasi-polynomial is divided into two terms. The first term is simply the denominator interval polynomial of the open loop system and the second term is the multiplication of the interval delay term in the numerator of the open loop system which is an interval polynomial. Each of these two terms of the characteristic quasi-polynomial makes their own value sets in the complex plane for a given frequency. In this paper, based on these two value sets and by using the zero exclusion principle, the robust stability of the closed loop system by applying a FOPID controller is analyzed. Finally, two numerical examples and an experimental verification are provided to demonstrate the effectiveness of the proposed method in the robust stabilization of fractional order plants with interval uncertainties and interval time delay.     

An evaluation of information behaviour studies through the Scholarly Capital Model

Influence and capital are two concepts used to evaluate scholarly outputs, and these can be measured using the Scholarly Capital Model as a modelling tool. The tool looks at the concepts of connectedness, venue representation, and ideational influence using centrality measures within a social network. This research used co‐authorships and h‐indices to investigate authors who have published papers in the field of information behaviour between 1980 and 2015 as extracted from Web of Science. The findings show a relationship between the authors’ connectedness and the venue (journal) representation. It could be seen that the venue (journal) influences the chance of citation, and equally, the prestige (centrality) of authors probably raises the citations of the journals. The research also shows a significant positive relationship between the venue representation and ideational influence. This means that a research work that is published in a highly cited journal will find more visibility and will receive more citations.     

不同哈萨克族儿童语言习得个案分析

语言环境对双语者的语言习得起到很大的作用。双语儿童对语言环境非常敏感。使用得当,孩子就会朝着双语方向正面发展,从而享受认知方面的优势,使用不得当,孩子就会朝着双语的负面方向发展,造成语言滞后乃至失语的状况。