Home  About us  Contact
 

Efficient Construction (efficient + construction)

Distribution by Scientific Domains
Chemistry85%

Selected Abstracts

Efficient Construction of Oxa- and Aza-[n.2.1] Skeletons: Lewis Acid Catalyzed Intramolecular [3+2],Cycloaddition of Cyclopropane 1,1-Diesters with Carbonyls and Imines,

ANGEWANDTE CHEMIE, Issue 18 2010
Siyang Xing Dr.
Brückenbau: Eine Lewis-Säure-vermittelte intramolekulare [3+2]-Cycloaddition zwischen Cyclopropan-1,1-diestern und Aldehyden, Ketonen oder Iminen (siehe Schema) eröffnet einen allgemeinen und effizienten Zugang zu verbrückten Oxa- und Aza[n.2.1]-Gerüsten (n=2,4). Als Anwendungsbeispiel wurde die Kernstruktur von Platensimycin aufgebaut. [source]

ChemInform Abstract: Efficient Construction of Oxa- and Aza-[n.2.1] Skeletons: Lewis Acid Catalyzed Intramolecular [3 + 2] Cycloaddition of Cyclopropane 1,1-Diesters with Carbonyls and Imines.

CHEMINFORM, Issue 36 2010
Siyang Xing
Abstract A Lewis acid promoted intramolecular [3+2] cycloaddition of cyclopropane 1,1-diesters with aldehydes, ketones, and imines is developed to provide a general and efficient strategy for construction of bridged oxa- and aza-[n.2.1] skeletons. [source]

An Efficient Construction of Bicyclic Systems Containing a Seven-Membered Ring by Tandem Ring-Closing Metathesis Reactions of Dienynes.

CHEMINFORM, Issue 19 2007
Francois-Didier Boyer
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

Double Ring-Closing Metathesis Reaction of Nitrogen-Containing Tetraenes: Efficient Construction of Bicyclic Alkaloid Skeletons and Synthetic Application to Four Stereoisomers of Lupinine and Their Derivatives

CHEMISTRY - A EUROPEAN JOURNAL, Issue 13 2004
Shengming Ma Prof.
Abstract The double ring-closing metathesis reaction of nitrogen-containing tetraenes was studied. The selectivity of the fused/dumbbell-type products can be controlled by the electronic/steric effects of the substituents attached to the CC bonds and the s - cis/s - trans conformational ratios of the substrates. This methodology has also been successfully applied to the enantioselective synthesis of four stereoisomers of lupinine and their derivatives. [source]

Strategic shotgun proteomics approach for efficient construction of an expression map of targeted protein families in hepatoma cell lines

PROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 12 2003
Chih-Lei Lee
Abstract An expression map of the most abundant proteins in human hepatoma HepG2 cells was established by a combination of complementary shotgun proteomics approaches. Two-dimensional liquid chromatography (LC)-nano electrospray ionization (ESI) tandem mass spectrometry (MS/MS) as well as one-dimensional LC-matrix-assisted laser desorption/ionization MS/MS were evaluated and shown that additional separation introduced at the peptide level was not as efficient as simple prefractionation of protein extracts in extending the range and total number of proteins identified. Direct LC-nanoESI MS/MS analyses of peptides from total solubilized fraction and the excised gel bands from one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis fractionated insolubilized fraction afforded the best combination in efficient construction of a nonredundant cell map. Compiling data from multiple variations of rapid shotgun proteomics analyses is nonetheless useful to increase sequence coverage and confidence of hits especially for those proteins identified primarily by a single or two peptide matches. While the returned hit score in general reflects the abundance of the respective proteins, it is not a reliable index for differential expression. Using another closely related hepatoma Hep3B as a comparative basis, 16 proteins with more than two-fold difference in expression level as defined by spot intensity in two-dimensional gel electrophoresis analysis were identified which notably include members of the heat shock protein (Hsp) and heterogeneous nuclear ribonucleoprotein (hnRPN) families. The observed higher expression level of hnRNP A2/B1 and Hsp90 in Hep3B led to a search for reported functional roles mediated in concert by both these multifunctional cellular chaperones. In agreement with the proposed model for telomerase and telomere bound proteins in promoting their interactions, data was obtained which demonstrated that the expression proteomics data could be correlated with longer telomeric length in tumorigenic Hep3B. This biological significance constitutes the basis for further delineation of the dynamic interactions and modifications of the two protein families and demonstrated how proteomic and biological investigation could be mutually substantiated in a productive cycle of hypothesis and pattern driven research. [source]

Scaffold Modeling Application in the Repair of Skull Defects

ARTIFICIAL ORGANS, Issue 4 2010
Weibing Wan
Abstract The repair of large segmental bone defects caused by trauma, inflammation, and surgery on tumors pose a major clinical challenge. Tissue-engineered bone is emerging as a good choice for prefabricating cellular scaffold, and computer-aided technologies and medical imaging have created new possibilities in biomedical engineering. An accurate and efficient construction of anatomic models is critical to the application of these computational methods. Such models must be validated prior to application. In this article, we explore the potential of combining these techniques to scaffold and repair a pediatric skull. Working under the hypothesis that the autogenously cultivated osteoblasts can be grown on individualized scaffolds to improve bone regeneration in skull defects, we focus our study on potential problems concerning the segmentation, reconstruction, and mesh simplification for a pediatric skull. We also propose a new framework to improve the accuracy of the model entity from image segmentation to mesh simplification. [source]