Akita University of Art: AUA Repository / 秋田公立美術大学リポジトリ
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Novel multispecies microbial consortia involved in lignocellulose and 5-hydroxymethylfurfural bioconversion
No full textTo develop a targeted metagenomics approach for the analysis of novel multispecies microbial consortia involved in the bioconversion of lignocellulose and furanic compounds, we applied replicated sequential batch aerobic enrichment cultures with either pretreated or untreated wheat straw as the sources of carbon and energy. After each transfer, exponential growth of bacteria was detected using microscopic cell counts, indicating that the substrate was being utilized. In batch, the final bacterial abundances increased from an estimated 5 to 8.7-9.5 log 16S rRNA gene copy numbers/ml. The abundances of fungal propagules showed greater variation, i.e., between 5.4 and 8.0 log ITS1 copies/ml. Denaturing gradient gel electrophoresis analyses showed that the bacterial consortia in both treatments reached approximate structural stability after six transfers. Moreover, the structures of the fungal communities were strongly influenced by substrate treatment. A total of 124 bacterial strains were isolated from the two types of enrichment cultures. The most abundant strains were affiliated with the genera Raoultella/Klebsiella, Kluyvera, Citrobacter, Enterobacter, Pseudomonas, Acinetobacter, Flavobacterium and Arthrobacter. Totals of 43 and 11 strains obtained from the untreated and pretreated substrates, respectively, showed (hemi)cellulolytic activity (CMC-ase and xylanase), whereas 96 strains were capable of growth in 7.5 mM 5-hydroxymethylfurfural. About 50 % of the latter showed extracellular oxidoreductase activity as detected by a novel iodide oxidation method. Also, (hemi)cellulolytic fungal strains related to Coniochaeta, Plectosphaerella and Penicillium were isolated. One Trichosporon strain was isolated from pretreated wheat straw. The two novel bacterial-fungal consortia are starting points for lignocellulose degradation applications.</p
'Expect the unexpected':Implications of effectual logic on the internationalization process
No full textInternational entrepreneurship literature has indicated that entrepreneurs often increase international activities along unexpected lines of reasoning without having a precise goal, resulting in "unplanned" internationalization. We argue that "unplanned" internationalization does not necessarily involve non-logical decisions; but, entrepreneurs can follow an effectual rather than causal logic and may base their decisions on the affordable loss principle rather than on the maximization of expected returns. Based on five case-studies, we discuss the implication of effectual decision-making on the internationalization process. We find that switching from causal to effectual logic allows firms to rapidly increase the level of commitment in the foreign market and could assist in overcoming liabilities of outsidership and, therefore, successfully increase the level of commitment in the foreign market. (C) 2013 Elsevier Ltd. All rights reserved.</p
To Accept or Refuse an Offer to Join the Board:Dutch Evidence
No full textPractitioners, academics and policymakers have come up with numerous proposals aimed at enhancing board effectiveness. Board composition is believed to be one of the most important determinants of board effectiveness and, hence, firm performance. Whereas the proposals typically focus on the qualities that non-executive directors should bring in - the demand side - in this study, we focus on the supply side of non-executive directors. More specifically, this study explores the personal motives for people to accept or turn down offers to become a non-executive director. The results based on Dutch survey data indicate that it is possible to identify a limited number of dimensions representing the motives to either accept or to turn down an offer. Using partial least squares (PLS), a form of structural equation modelling that is particularly useful for small samples, we find "extrinsic motives" and "intrinsic motives" as reasons for both accepting and rejecting offers. We are able to identify a motive for accepting an offer that is related to the quality of management and supervision. Furthermore, our analysis indicates a third motive for rejection that we labelled "reputational concern". In addition, we find that directors' characteristics, such as experience and multiple directorships, explain the extent to which the various motives are used. Lastly, we find that particularly the intrinsic motives drive the extent to which a director accepts offers to join supervisory boards. We discuss how these findings affect corporate practices of recruiting non-executive directors.</p
Private acquisition gains:A contingent claims explanation
No full textThis paper studies announcement returns of Western European acquisitions of private and public targets. It uses a contingent claims perspective to offer a new explanation for the difference in abnormal returns between acquirers of private and public targets. In this context, an acquisition is analogous to buying a call option and the value of the acquirer increases with uncertainty about its growth prospects (options). We test this idea by studying the relation between announcement returns and acquirer's characteristics that proxy for the existence of growth options. Consistent with the contingent claims hypothesis, the private acquisition gains are associated with the combined effects of growth options (having higher runup before the acquisition announcement) with low level of leverage (near-all equity capital) and with uncertainty (measured by age and analyst coverage of acquirers).</p
The YmdB Phosphodiesterase Is a Global Regulator of Late Adaptive Responses in Bacillus subtilis
No full textBacillus subtilis mutants lacking ymdB are unable to form biofilms, exhibit a strong overexpression of the flagellin gene hag, and are deficient in SlrR, a SinR antagonist. Here, we report the functional and structural characterization of YmdB, and we find that YmdB is a phosphodiesterase with activity against 2′,3′- and 3′,5′-cyclic nucleotide monophosphates. The structure of YmdB reveals that the enzyme adopts a conserved phosphodiesterase fold with a binuclear metal center. Mutagenesis of a catalytically crucial residue demonstrates that the enzymatic activity of YmdB is essential for biofilm formation. The deletion of ymdB affects the expression of more than 800 genes; the levels of the σD-dependent motility regulon and several sporulation genes are increased, and the levels of the SinR-repressed biofilm genes are decreased, confirming the role of YmdB in regulating late adaptive responses of B. subtilis
Tribological properties of nc-TiC/a-C:H coatings prepared by magnetron sputtering at low and high ion bombardment of the growing film
No full textTwo series of nc-TiC/a-C:H coatings were deposited by a hybrid PVD–PECVD process of titanium sputtering in argon/acetylene atmosphere at two configurations of magnetic field resulting in different impinging ion fluxes on the growing film. The composition of the coatings was varied by changing the acetylene gas flow during the depositions. Tribological tests were performed under conditions of emulating dry machining using 100Cr6 steel ball and silicon nitride ball as sliding counterparts. High temperature tribo-tests at 300 °C and 500 °C were performed with silicon nitride ball counterpart to examine the thermal stability of the coatings deposited at 320 °C. Special attention was paid to design coatings with optimal chemical composition for high hardness. The coefficient of friction (CoF) and wear as a function of C/Ti are presented. It is observed that in the range of 1 < C/Ti < 2 the CoF is largely independent of the ion flux during the deposition and is ~ 0.2–0.3. The CoF then decreases with increasing carbon content up to a certain limit. Highest carbon-containing coating shows an increased CoF and wear. The coatings became strongly oxidized after the high temperature test. The CoF for coatings in the high hardness region is stable around 0.3 for the whole test at 300 °C, the CoF at 500 °C was stable at ~ 0.2 for the first half of the test, and then the coating failed. The coating in the wear tracks was mostly delaminated
