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31.
32.
This study described palladium-catalyzed chemoselective direct α-arylation of carbonyl compounds with chloroaryl triflates in the Ar–Cl bond. The Pd/SelectPhos system showed excellent chemoselectivity toward the Ar–Cl bond in the presence of the Ar–OTf bond with a broad substrate scope and excellent product yields. The electronic and steric hindrance offered by the –PR2 group of the ligand with the C2-alkyl group was found to be the key factor affecting the reactivity and chemoselectivity of the α-arylation reaction. The chemodivergent approach was also successfully employed in the synthesis of flurbiprofen and its derivatives (e.g., –OMe and –F).Palladium-catalyzed chemoselective direct α-arylation of carbonyl compounds with chloroaryl triflates in the Ar–Cl bond is reported. The effects of –PR2 and C2-alkyl groups of the ligands are investigated using experimental and computational methods. 相似文献
33.
Chau O. Shillor M. Sofonea M. 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2004,55(1):32-47
A model for the dynamic, adhesive, frictionless contact
between a viscoelastic body and a deformable foundation is
described. The adhesion process is modeled by a bonding field on
the contact surface. The contact is described by a modified normal
compliance condition. The tangential shear due to the bonding
field is included. The problem is formulated as a coupled system
of a variational equality for the displacements and a differential
equation for the bonding field. The existence of a unique weak
solution for the problem is established, together with a partial
regularity result. The existence proof proceeds by construction of
an appropriate mapping which is shown to be a contraction on a
Hilbert space. 相似文献
34.
35.
A method of generating a 3-D image of an object from its shadowgraphs is described. Unlike the previous techniques, this method involves a process of phase implantation into the shadowgrams by means of holography. We emphasize the reconstruction of a real image, so that precise measurements of its structure are possible. Results of the experiment are shown. 相似文献
36.
Wei-Gang Hu Scott Jager Damon Chau Dave Mah Les P. Nagata 《Applied biochemistry and biotechnology》2010,160(4):1206-1216
In order to develop a recombinant full-length human anti-botulinum neurotoxin A (BoNT/A) antibody, human peripheral blood
mononuclear cells (PBMC) were collected from three healthy volunteers and induced for BoNT/A-specific immune response by in
vitro immunization. The genes encoding human Fd fragment, consisting of antibody heavy chain variable region and constant
region 1 with the genes encoding antibody light chain, were cloned from the immunized PBMC. Afterwards, one combinatory human
antigen-binding fragment (Fab) library was constructed using a lambda phage vector system. The size of the constructed library
was approximately 105
Escherichia coli transformants. After screening the library by BoNT/A antigen using a plaque lifting with immunostaining approach, 55 clones
were identified as positive. The Fab gene of the most reactive clone exhibiting particularly strong BoNT/A binding signal
was further subcloned into a full-length human IgG1 antibody gene template in an adenoviral expression vector, in which the
heavy and light chains were linked by a foot-and-mouth-disease virus-derived 2A self-cleavage peptide under a single promoter.
After the full-length human IgG1 was expressed in mammalian cells and purified with protein L column, sodium dodecyl sulfate-polyacrylamide
gel electrophoresis showed that the heavy and light chains of the antibody were cleaved completely. The affinity expressed
as the dissociation constant (K
d) for the recombinant human antibody to bind to BoNT/A was determined by indirect enzyme-linked immunosorbent assay and results
confirmed that the recombinant full-length human antibody retained BoNT/A-binding specificity with K
d value of 10−7 M. 相似文献
37.
Wan YS Chau JL Gavriilidis A Yeung KL 《Chemical communications (Cambridge, England)》2002,(8):878-879
A zeolite-based microengineered reactor was fabricated and tested for 1-pentene epoxidation over titanium silicalite-1 (TS-1) catalyst, which has been selectively incorporated within the microreactor channel using a new synthesis procedure. 相似文献
38.
The determinatin of the concentration of major steel forming elements in 2–5 g steel samples by PGAA and reference to synthetic standard or single comparator is presented. The relative standard deviation is approximately 5%. The analysis time is about 60 min per sample. 相似文献
39.
40.
A thin-beam holographic reconstruction technique to study the 3-D refractive index field of a phase object is described. The advantages and drawbacks of this method are discussed. 相似文献