Total synthesis of (+)-SCH 351448

Total synthesis of SCH 351448 was accomplished employing the ring-closing olefin metathesis reaction for the preparation of the 28-membered macrodiolide.     

The reaction of N-methyl-1,2,4-triazoline-3,5-dione with tetracyclopropylethylene. Formation of an unusual meso-ionic product and its rearrangement to the diazetidine

The reaction of N-methyl-1,2,4-triazoline-3,5-dione and tetracyclopropylethylene results in the quantitative formation of a meso-ionic compound. The formation of this unusual compound is likely the result of the unique conformational and steric properties of the cyclopropyl groups which inhibit the expected reaction pathways. The meso-ionic compound undergoes an unprecedented rearrangement to the diazetidine upon warming to 55 degrees C.     

A new imidazolium cavitand for the recognition of dicarboxylates

[structure: see text] A new cavitand bearing four imidazolium groups was synthesized for the recognition of anions through (C-H)+...X- hydrogen bond formation. The binding properties toward various anions including dicarboxylates were examined on the basis of 1H NMR spectroscopic experiments.     

Quasiscarred resonances in a spiral-shaped microcavity

We study resonance patterns of a spiral-shaped dielectric microcavity with chaotic ray dynamics. Many resonance patterns of this microcavity, with refractive indices n=2 and 3, exhibit strong localization of simple geometric shape, and we call them quasiscarred resonances in the sense that there is, unlike conventional scarring, no underlying periodic orbits. It is shown that the formation of a quasiscarred pattern can be understood in terms of ray dynamical probability distributions and wave properties like uncertainty and interference.     

Oxidative coupling of epigallocatechin gallate amplifies antioxidant activity and inhibits xanthine oxidase activity

Oxidative coupling of epigallocatechin gallate resulted in great improvement in antioxidant activity such as radical scavenging activity against superoxide anion and in activity to inhibit xanthine oxidase, offering high potential as a therapeutic agent for prevention of xanthine oxidase-induced diseases such as gout.     

A copper-free Sonogashira coupling reaction in ionic liquids and its application to a microflow system for efficient catalyst recycling

[reaction: see text] The PdCl2(PPh3)2-catalyzed Sonogashira coupling reaction, in good to high yields, was performed in an ionic liquid ([BMIm][PF6]) in the absence of a copper salt. The use of an ionic liquid allows for the facile separation and recycling of the catalyst. The application of the above reaction in a microflow system in conjunction with an IMM micromixer was also successful.     

A parallel approach to the discovery of carrier delivery vehicles to enhance antigen immunogenicity

As part of an ongoing effort to generate human and murine monoclonal antibodies against poorly immunogenic tumor-associated antigens we have merged the rapidly expanding disciplines of parallel polymer synthesis and controlled-release technology with immunology to produce a rapid and generic approach to improve the immunogenicity of carrier-bound antigens. The process involves three stages: An array of cross-linked hydrogel materials containing a carrier protein (at various concentrations) is prepared in parallel in one step. The array is then screened in mice to determine the most effective hydrogel at enhancing the immunogenicity of the encapsulated versus nonencapsulated carrier. Finally, the most efficient hydrogel is prepared containing the critical carrier-antigen conjugate and is used for immunization protocols. The strategy was successful for the BSA-glycoconjugate of the tumor-associated antigen GM3 analogue 4. When encapsulated within the hydrogel array member most efficient at elevating BSA immunogenicity, the BSA-4 glycoconjugate was significantly more immunogenic that when administered as a free antigen.     

Preparation and characterization of ZnTe thin films by SILAR method

Nanocrystalline zinc telluride (ZnTe) thin films were prepared by using successive ionic layer adsorption and reaction (SILAR) method from aqueous solutions of zinc sulfate and sodium telluride. The films were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis and optical absorption measurement techniques. The synthesized ZnTe thin films were nanocrystalline with densely aggregated particles in nanometer scale and were free from the voids or cracks. The optical band gap energy of the film was found to be thickness dependent. The elemental chemical compositional stoichiometric analysis revealed good Zn:Te elemental ratio of 53:47.     

Analysis of Mutation Effects on PIDDosome Core Complex

PIDDosome is a recently-identified caspase-2-activating molecular complex formed by genotoxic stress that leads to caspase-2-dependent apoptosis. PIDD, RAIDD, and caspase-2 are three protein components of PIDDosome. The core portion of PIDDosome is formed by the unique screw rotation of seven RAIDD DD and five PIDD DD. In the current study, we found that two mutations generated during structural-based mutagenesis studies, Q169E and R170A on RAIDD DD, were dominant negative. Because the discovery of dominant-negative mutants might implicate the disease and therapeutic intervention, newly identified dominant-negative mutants could lead to new potential applications for treatment of human diseases caused by excessive or reduced apoptosis.