A series of C7-O- and C20-O-amidated 2,3-dehydrosilybin (DHS) derivatives ((+/-)-1a-f and (+/-)-2), as well as a set of alkenylated DHS analogues ((+/-)-4a-f), were designed and de novo synthesized. A diesteric derivative of DHS ((+/-)-3) and two C23 esterified DHS analogues ((+/-)-5a and (+/-)-5b) were also prepared for comparison. The cell viability of PC12 cells, Fe(2+) chelation, lipid peroxidation (LPO), free radical scavenging, and xanthine oxidase inhibition models were utilized to evaluate their antioxidative and neuron protective properties. The study revealed that the diether at C7-OH and C20-OH as well as the monoether at C7-OH, which possess aliphatic substituted acetamides, demonstrated more potent LPO inhibition and Fe(2+) chelation compared to DHS and quercetin. Conversely, the diallyl ether at C7-OH and C20-OH was more potent in protection of PC12 cells against H(2)O(2)-induced injury than DHS and quercetin. Overall, the more lipophilic alkenylated DHS analogues were better performing neuroprotective agents than the acetamidated derivatives. The results in this study would be beneficial for optimizing the therapeutic potential of lignoflavonoids, especially in neurodegenerative disorders such as Alzheimer's and Parkinson's disease.

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This paper presents a new method for estimating the base capacity of open-ended steel pipe piles in sand, a difficult problem involving great uncertainty in pile foundation design. The method, referred to as the Hong Kong University (HKU) method, is based on the cone penetration test (CPT), and takes into consideration the mechanisms of annulus and plug resistance mobilization. In this method the annulus resistance is properly linked to the ratio of the pile length to the diameter-a key factor reflecting the influence of pile embedment-whereas the plug resistance is related to the plug length ratio, which reflects the degree of soil plugging in a practical yet rational way. The cone tip resistance is averaged over a zone in the vicinity of the pile base by taking into account the failure mechanism of the piles in sand, the condition of pile embedment (i.e., full or partial embedment), and the effect of soil compressibility. The predictive performance of the new method is assessed against a number of well-documented field tests including two fully instrumented large-diameter offshore piles, and through comparisons with major CPT-based methods in current engineering practice. The assessment indicates that the HKU method has attractive capabilities and advantages that render it a promising option.

Purpose – The purpose of this paper is to explore the structure of leader communication style in the context of organizational change. In doing so, the authors intend to shed more light on how leaders can effectively communicate change projects to their subordinates, which is viewed as the key to implementing change initiatives. Design/methodology/approach – This paper builds an integrated conceptual model for understanding leader’s communication style and subordinates’ commitment to change. By analyzing subordinates’ different fears of change, the paper further proposes a multidimensional structure of leader communication style in the context of change. The authors then develop a scale to measure these different dimensions and test the relationship between the proposed communication style and subordinates’ affective commitment to change. Findings – Leader communication style in the context of change is found to be composed of five dimensions: hope orientation, reality orientation, subordinate orientation, support orientation, and enforcement orientation. A cross-level field study of 31 teams and 194 members shows that hope orientation, subordinate orientation, and support orientation are positively associated with subordinates’ affective commitment to change. Originality/value – This paper identifies a new structure of leader communication style that will lead to a richer understanding of how leaders communicate to their subordinates in the context of change. It also contributes to the leadership literature by implying effective ways of communicating change projects.