134,111 research outputs found
How ICTs Raise Manufacturing Performance: Firm-level Evidence in Southeast Asia.
No full textThis paper examines the effects of information and communication technologies (ICTs) on business performance, using firm-level data obtained through a questionnaire survey in four ASEAN countries (Indonesia, The Philippines, Thailand and Vietnam). Sources of information and new technologies exchanged via ICTs by firms are also explored to investigate the mechanism behind ICT adoption. Empirical results verify that the introduction of ICT to reorganize business processes is significantly correlated with business performance, in particular the development of export markets and improvement of production management. ICTs facilitate access to information and technologies accumulated in in-house departments and joint-venture (JV) affiliates of the respondent firms. There are considerable differences between multinational companies (MNCs)/JVs and local firms. MNCs/JVs make use of information and technologies obtainable via ICTs from their own R&D departments, JVs established with local partners and foreign-owned suppliers/customers to improve factory management, mostly for product quality improvement and production cost reduction. In contrast, local firms interconnect their own R&D departments via ICTs to enhance their business performance in broader areas than MNCs/JVs, including the development of export markets.
Conformational flexibility of membrane proteins in electric fields I. Ultraviolet absorbance and light scattering of bacteriorhodopsin in purple membranes
No full textTsuji K, Neumann E. Conformational flexibility of membrane proteins in electric fields I. Ultraviolet absorbance and light scattering of bacteriorhodopsin in purple membranes. Biophysical Chemistry. 1983;17(2):153-163
Structural changes in bacteriorhodopsin induced by electric impulses
No full textTsuji K, Neumann E. Structural changes in bacteriorhodopsin induced by electric impulses. International Journal of Biological Macromolecules. 1981;3(4):231-242
The ion-pair concept in macromolecular dynamics
No full textNeumann E, Tsuji K, Schallreuter D. The ion-pair concept in macromolecular dynamics. Bioelectrochemistry and Bioenergetics. 1984;13(4-6):419-428
A Stereoconvergent Tsuji–Trost Reaction in the Synthesis of Cyclohexenyl Nucleosides
No full textA highly regio- and stereoselective route to d- and l-cyclohexenyl nucleosides has been devised, using the Tsuji–Trost reaction as the key step. Contrarily to the widely accepted mechanism (involving a net retention of configuration), the reaction proceeded in a highly stereoconvergent manner, providing cis nucleosides regardless of the relative configuration of the starting materials. DFT calculations confirmed the experimental data while suggesting the origin of the stereochemical reaction outcome
Apport des liquides ioniques à la réaction de Tsuji-Trost
No full textCe travail est consacré à l exploitation de liquide ionique en catalyse organométallique. La réaction modèle choisie est la substitution allylique de Tsuji-Trost impliquant des acétates allyliques. Les réactions ont été étudiées en phase liquide ionique homogène ou supportée sur un biopolymère (SILC). Nous nous sommes tout d abord intéressés à l exploitation de matériaux catalytiques originaux à base de liquide ionique supporté sur un biopolymère, le chitosane (chitosane-SILC). Après préparation et caractérisation des matériaux chitosane-SILC, ils ont été appliqués à la version racémique et énantiosélective de la réaction de Tsuji-trost. Différentes voies de préparation du support chitosane ont été testées et l influence de celui-ci sur les propriétés catalytiques des chitosane-SILC a été étudiée. Ensuite, les liquides ioniques, en phases homogène et supportée, ont été appliqués à la substitution d alcools allyliques non-activés. Les résultats montrent que cette réaction est possible dans ces milieux liquides ioniques avec des nucléophiles aminés et carbonés. L utilisation d acide boronique, comme activant, permet d améliorer l activité et le recyclage du système catalytique.Catalytic homogeneous and supported ionic liquid phases were developed for organometallic catalysis, in the case of the Tsuji-Trost allylic substitution. We first used a catalytic material based on an ionic liquid phase immobilised on chitosan (chitosan-SILC). Different SILC were prepared, characterised, and applied to the classical Tsuji-Trost reaction with carbon nucleophile, in both racemic and enantioselective versions. The influence of the conditioning and the drying process of the chitosan support on the catalyst s activity and selectivity was studied. In a second part, homogeneous and supported ionic liquid catalytic phases were applied for the more profitable direct use of allylic alcohols in the Tsuji-Trost reaction. The direct substitution of allylic alcohols by primary and secondary amines and carbon nucleophiles were successfully conducted in ionic liquid. The use of a catalytic amount of an additive such as boronic acid to activate the alcohol function greatly improves the catalytic activity and the recycling of the catalyst.CAEN-BU Sciences et STAPS (141182103) / SudocSudocFranceF
MeSH term explosion and author rank improve expert recommendations
No full textInformation overload is an often-cited phenomenon that reduces the productivity, efficiency and efficacy of scientists. One challenge for scientists is to find appropriate collaborators in their research. The literature describes various solutions to the problem of expertise location, but most current approaches do not appear to be very suitable for expert recommendations in biomedical research. In this study, we present the development and initial evaluation of a vector space model-based algorithm to calculate researcher similarity using four inputs: 1) MeSH terms of publications; 2) MeSH terms and author rank; 3) exploded MeSH terms; and 4) exploded MeSH terms and author rank. We developed and evaluated the algorithm using a data set of 17,525 authors and their 22,542 papers. On average, our algorithms correctly predicted 2.5 of the top 5/10 coauthors of individual scientists. Exploded MeSH and author rank outperformed all other algorithms in accuracy, followed closely by MeSH and author rank. Our results show that the accuracy of MeSH term-based matching can be enhanced with other metadata such as author rank
^<15>N_2^+ (D\u27^2II_<gr>-A^2II_<ui>) Emission Resulting from the He^+ + ^<15>N_2 Charge Transfer Reaction
No full textThe ^<15>N_2^+(D\u27^2II_<gr>-A^2II_<ui>) emission system arising from the He^++ ^<15>N_2 reaction has been observed both in a flowing afterglow and in a low-pressure chamber combined with flowing afterglow. The absolute vibrational quantum numbers for the D\u27-A system have been proposed by measuring isotopic shifts between ^<15>N_2^+and ^<14>N_2^+ bands
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Mechanistic Investigations into the Palladium-Catalyzed Decarboxylative Allylic Alkylation of Ketone Enolates Using the PHOX Ligand Architecture
No full textPalladium-catalyzed asymmetric allylic alkylation has become a large and important field for chemical synthesis. Many methodologies in this field offer mild conditions under which challenging and important molecular features can be reliably synthesized, including chiral all-carbon quaternary stereocenters. As a result, palladium- catalyzed asymmetric allylic alkylation has found significant use in total synthesis, and growing use in industry. While the general process of palladium-catalyzed asymmetric allylic alkylation has been studied for decades, there have been a number of recent modifications and developments, such as asymmetric versions of decarboxylative allylic alkylation procedures that are not yet well understood. The development of future implementations and improvements to palladium-catalyzed asymmetric allylic alkylation and related methodologies is expected to be facilitated by a better understanding of these more recent developments, and thus further mechanistic investigation is warranted.
Reported herein is a set of investigations into the palladium-catalyzed decarboxylative asymmetric allylic alkylation of ketone enolates using the PHOX ligand architecture. By monitoring the reaction via 31P NMR, a series of previously unidentified key intermediates is discovered. Two representatives of these key intermediates are isolated and characterized. The solution behavior of these species under reaction-like conditions is studied along with a few novel and related complexes. The role of these intermediates and their impact on the behavior of the reaction and product formation is discussed. Previously confounding experimentally observed behavior for this methodology is rationalized via the properties elucidated for these discovered intermediates.</p
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