The first direct enantioselective catalytic alpha-oxidation of carbonyls has been accomplished. The use of enamine catalysis has provided a new organocatalytic strategy for the enantioselective oxyamination of aldehydes, to generate alpha-oxyaldehydes, important chiral synthons for natural product and medicinal agent synthesis. The use of l-proline as the asymmetric catalyst has been found to m...

While the modular construction of molecules from suitable building blocks is a powerful means to more rapidly generate diversity than through customized syntheses, further evolution underlying coupling methodology key realize widespread applications. We herein disclose complementary approach widely employed Suzuki strategy boron containing precursors, which relies on organogermane as orthogonal...

In this paper, the dynamic response of a three-rotor flexible coupling to the angularmisalignment has been studied. The coupling is a power transmission agent between the motor andgearbox, in the power transmission system of SAG Mill (semi autogenously mill) in the Gol-e-Gohariron ore complex in Sirjan, Iran. Degrees of freedom of the system are the model's lateral deflectionsand the rigid-body...

  A new bioactive proline-rich cyclohexapeptide - diandrine C (6), previously isolated from whole plant of Drymaria diandra (Caryophyllaceae), was synthesized through coupling reactions of tetrapeptide unit Boc-Gly-l-Pro-l-Tyr-l-Trp-OH with dipeptide unit l-Pro-Gly-OMe using N,N-diisopropylcarbodiimide (DIPC) as the coupling agent, followed by cyclization of l...

The effect of wood flour and coupling agent content on the hygroscopic thickness swelling rate of polypropylene composites was investigated in this study. To meet this objective, the wood flour was compounded with polypropylene and coupling agent in an internal mixer; then the samples were fabricated by injection molding. The concentration was varied from 40 to 60% for wood flour and from 0 to ...

BACKGROUND AND OBJECTIVES Acrylic resin ruled the dental profession for 60 years, and this success is attributed to its aesthetics, handling properties, physical and biological compatibility, its stability in oral environment and its cost effectiveness. The objective of this study is to evaluate and compare the bond strength of acrylic resin teeth treated with various conditioning materials lik...

The efficient synthesis of highly substituted cyclopentanols is an important task given the prevalence of this class of compounds in nature. Nitrocyclopentanols are of particular value due to the rich chemistry associated with the nitro group and their potential use as aminocyclopentitol progenitors. Aminocyclopentitols have generated considerable attention because of their significant biologic...

To be effective, a learning process must be adapted to the learner’s context. Such a context should be described at least from pedagogical, technological and learning perspectives. Current e-Learning approaches either fail to provide learning experiences within rich contexts, thus hampering the learning process, or provide extremely contextualized content that is highly coupled with context inf...

ences of the Artificial with a parable about an ant making her way home across a beach and comments that the complexity of her route is not a manifestation of any complex, goal-seeking behavior within the ant but rather reflects the complexity of the environment. The ant “must adapt [her] course repeatedly to the difficulties [she] encounters and often detour uncrossable barriers.” The question...