Acetogenin and Prenylated Flavonoids from Helminthostachys zeylanica with Inhibitory Activity on Superoxide Generation and Elastase Release by Neutrophils

One new acetogenin, 6-hydroxy-8-pentadecyloxocane-2,7-dione (1), and four new prenylated flavonoids, 4 '' a,5 '',6 '',7 '',8 '',8 '' a-hexahydro-5,3',4'-trihydroxy-5 '',5 '',8 '' a-trimethyl-4H-chromeno[2 '',3 '': 7,6] flavone (2), 4 '' a,5 '',6 '',7 '',8 '',8 '' a-hexahydro5,3', 4',-trihydroxy-5 '',5 '',8 '' a-trimethyl-4Hchromeno[2 '', 3 '': 7,8] flavone (3), 2-(3,4-dihydroxyphenyl)6-((2,2-dimethyl-6-methylenecyclohexyl) methyl)-5,7-dihydroxy-chroman-4-one (4), and 2-(3,4-dihydroxy-2-[(2,6,6-trimethylcyclohex-2-enyl) methyl] phenyl)-3,5,7-trihydroxy-4H-chromen-4-one (5), together with six known compounds, were isolated and purified from the rhizomes of Helminthostachys zeylanica by column chromatography and high performance liquid chromatography (HPLC) via bioactivity-guided fractionation isolation. The structures of the new isolates were elucidated by spectroscopic methods. Compounds 1, 3, and 5 showed inhibitory activities on either superoxide anion generation or elastase release by human neutrophils in response to formyl-L-methionyl-L-leucyl-L-phenylalanine/cytochalasin B (FMLP/CB)

Organizational slack: is more or less better?

Purpose - The purpose of this paper is to attempt to reconcile previous views of the relationship between organizational slack and performance by examining the influences of heterogeneous corporate strategy and different slack resources. Differences in performance resulting from variations in slack can also be moderated by strategy. Design/methodology/approach - The proposed model was tested by examining operating and financial information from 529 Taiwan high-tech companies during the period 1997-2005. Owing to the study, data were both cross-sectional (across firms) and time series (over years), a panel data approach were applied for hypothesis testing. Findings - The results broadly demonstrate that relationships differ based on strategy and organizational slack. Additionally, this study is the first to empirically identify a U-shaped relationship between slack and performance, indicating that, in certain circumstances, either more or less slack is better for performance. Originality/value - The results support a dynamic perspective regarding the slack-performance relationship was proposed for different strategy and different types of slack resources. Moreover, the authors argue that not only resource heterogeneity, but also firm strategic orientation, should be considered when performing change activities. Restated, the authors believe the best interest for a firm aspiring to conduct organizational change behaviors is to maintain the "fitness" among the environment, strategy orientation, and slack resources will induce higher performance. This study, thus demonstrates how organizational change behaviors are influenced by slack resources and strategy heterogeneity

Firm Resources and Corporate Venturing Investment

Corporate venturing (CV) in which established firms invest in new entrepreneurial businesses involves identifying opportunities and creating new combinations of resources to seize opportunities. Moving beyond literature that has focused predominantly on the consequences of CV, we adopt a resource-based view to examine how knowledge-based and organizational-slack resources relate to the level of firm CV. The implications of the findings for future research are discussed. Copyright (c) 2011 ASAC. Published by John Wiley & Sons, Ltd

Can external corporate venturing broaden firm's technological scope? The role of complementary assets

This study applies two theoretical perspectives-resource-based view (RBV) and organizational learning-to explore how a firm's external corporate venturing (CV) influences its technological scope. Using data from 583 electronics and information technology firms in Taiwan for the period from 1997 to 2006, the results indicate that external CVs facilitate an established firm's broadening of its technological scope. Moreover, this study calls into question the idea that a firm's decisions regarding technological scope may be due to a specific factor that governs the extent of technological specialization and diversification. We identify this factor as the complementary assets of established firms. This study, thus, investigates whether complementary assets moderate the relationship between external CV in established firms and those firms' technological scope. The analytical results also support the idea that increasing investments in specialized complementary assets will urge firms engaged in external CV to concentrate on their technological scope. Therefore, this study addresses the notion that concentrated technological scope is the conjunction of technological capabilities and complementary assets, not determined by either individually. (C) 2010 Elsevier B.V. All rights reserved

Technological scope: diversified or specialized

Although the topic of technological diversification has been a major source of research, only a few studies have explored the determinant variables of technological scope decisions. The present study enhances our understanding of the determinants of a firm's technological scope strategy. After reviewing the related literatures, we proposed and empirically tested a conceptual model from the perspective of the firm's environment, strategic orientation, and resources. The results suggest that the coherence between technological scope decisions and proposed model is significantly related to performance

Technological diversification, complementary assets, and performance

Most research on technological diversification or complementary assets has been carried out in isolation when assessing their effects on performance. In this study, we posit that technological diversification and performance are positively linked and that specialized complementary assets have a moderating effect on this relationship. This study also finds that different specialized complementary assets have distinctive moderating effects on the relationship between technological diversification and performance. We conclude that maintaining a coherent relationship between technological diversification and specialized complementary assets give firms generates competitive advantage. (C) 2007 Elsevier Inc. All rights reserved

Technological Diversification and Organizational Divisionalization: The Moderating Role of Complementary Assets

This study uses data on 582 electronics and information technology firms in Taiwan for the period 1997-2005 to investigate the hypothesis that technological diversification increases the extent of organizational divisionalization under firm growth. This study applies competence-based theory to argue that firms spread the technological competence base to achieve firm growth. However, in the face of firm growth, managers of multi-technology firms often utilize a multi-division structure to manage their various technologies based on their operating characteristics or needs. Furthermore, the findings of this study indicate that complementary assets moderate the negative relationship between technological diversification and organizational divisionalization. For firms with specialized complementary assets, multi-technology firms may be observed to consolidate related-technology activities into fewer divisions, facilitating the utilization of these complementary assets in conjunction with other divisions

Enhanced preference for pi-bond containing substrates is correlated to Pro110 in the substrate-binding tunnel of Escherichia coli thioesterase I/protease I/lysophospholipase L-1

Escherichia coli thioesterase I/protease I/lysophospholipase L, (TAP) possesses multifunctional enzyme with thioesterase, esterase, arylesterase, protease, and lysophospholipase activities. Leu109, located at the substrate-binding tunnel, when substituted with proline (Pro) in TAP, shifted the substrate-preference from medium-to-long acyl chains to shorter acyl chains of triglyceride and p-nitrophenyl ester, and increased the preference for aromatic-amino acid-derived esters. In the three-dimensional TAP structures, the only noticeable alteration of backbone and side chain conformation was located at the downstream Pro 110-Alal 23 region rather than at Pro 109 itself The residue Pro I 10, adjacent to Leu 109 or Pro 109, was found to contribute to the substrate preference of TAP enzymes for esters containing acyl groups with pi bond(s) or aromatic group(s). Some of the interactions between the enzyme protein and the substrate may be contributed by an attractive force between the Pro I 10 C-H donor and the substrate pi-acceptor. (c) 2007 Elsevier B.V. All rights reserved

Historic Perspectives on Annonaceous Acetogenins from the Chemical Bench to Preclinical Trials

Studies on the Annonaceous acetogenins began after the first cytotoxic acetogenin, uvaricin, was isolated in 1982. This attractive finding made many medicinal and natural product chemists direct their efforts on the isolation and identification of these classes of compounds. As more Annonaceous acetogenins were isolated, more information about them was uncovered. From their structural identification to the total synthesis of natural product analogues and from cell-based screening and molecular-based targeting to animal testing, the mechanisms of action of the Annonaceous acetogenins became clearer. The purpose of this review is to give an account of recent studies on this class of compounds and their analogues, which will aid us not only in clarifying how the Annonaceous acetogenins act but also in establishing principles for the further development of this class of compounds

Low potential detection of nicotine at multiwalled carbon nanotube-alumina-coated silica nanocomposite

Electrocatalytic oxidation of nicotine at multiwalled carbon nanotube (MWCNT)-alumina-coated silica (ACS) nanocomposite modified glassy carbon electrode are described. The sensing performance of the MWCNT-ACS nanocomposite modified glassy carbon electrode for the electrooxidation of nicotine was investigated using cyclic voltammetry and amperometry in 0.1 M phosphate buffer solution (pH 8). The MWCNT-ACS nanocomposite modified glassy carbon electrode exhibited the abilities to decrease the electrooxidation potential, to prevent the electrode surface fouling, and to raise the current responses. The MWCNT-ACS nanocomposite responded rapidly to nicotine with a sensitivity of 1.786 A M(-1) cm(-2) and a detection limit of 1.42 mu M (according to 3 sigma criterion). A signal almost 180 times more sensitive was obtained at MWCNT-ACS nanocomposite modified glassy carbon electrodes as compared to bare glassy carbon electrode. The nicotine oxidation potential obtained in this study is much lower than that at boron-doped diamond electrodes. (C) 2009 Elsevier B.V. All rights reserved