Microscopic aspects of autoschizic cell death in human ovarian carcinoma (2774) cells following vitamin C, vitamin K3 or vitamin C:K3 treatment.

Human ovarian carcinoma cells (MDAH 2774) were treated with sodium ascorbate (VC), menadione (VK3), or with a VC:VK3 combination for 1 h and then studied using light microscopy (LM) and scanning (SEM) and transmission electron (TEM) microscopy. Plasma membrane damage (blisters and blebs, hairy aspect) results from vitamin C (VC) treatment, while cytoskeletal damage and self-morsellation are caused by vitamin K3 (VK3) treatment. VC:VK3-treated cells exhibit exacerbated injuries characteristic of both VC and VK3 treatment as well as a significant decrease in cell diameters from 20-35 microm for control cells to 7-12 microm for VC:VK3 treatment. Moreover, after a 1-h exposure to the vitamin combination, autoschizis (43%), apoptosis (3%), and oncosis (1.9%) are observed at the percentages indicated. All cellular changes associated with autoschizis observed with SEM were confirmed by LM and TEM observations and are consistent with cell death by autoschizis: decrease in cell size, cytoplasmic self-excisions, degradation of the nucleus and nucleolus without formation of apoptotic bodies and, ultimately, karyorrhexis and karyolysis. These results also suggest that the vitamin combination may find clinical use in the treatment of ovarian cancer.     

Synthesis of amphidinolide T1 via catalytic, stereoselective macrocyclization

Two nickel-catalyzed reductive coupling reactions of alkynes were instrumental in a modular, stereoselective synthesis of amphidinolide T1 (1). The C13-C21 fragment was prepared from two simple starting materials that were joined in a catalytic alkyne-epoxide fragment coupling operation, whereas an intramolecular aldehyde-alkyne reductive coupling simultaneously formed the final carbon-carbon bond of the macrocycle and established the C13 carbinol configuration with complete selectivity in the desired fashion.     

Monotonicity of the mean order of subtrees

This paper is concerned with the average number of nodes in certain families of subtrees of a tree. It is shown that this average increases when the underlying tree is enlarged and decreases if the family itself is enlarged within the same underlying tree.     

Metathesis depolymerization for removable surfactant templates

Current methodologies for the production of meso- and nanoporous materials include the use of a surfactant to produce a self-assembled template around which the material is formed. However, post-production surfactant removal often requires centrifugation, calcination, and/or solvent washing which can damage the initially formed material architecture(s). Surfactants that can be disassembled into easily removable fragments following material preparation would minimize processing damage to the material structure, facilitating formation of templated hybrid architectures. Herein, we describe the design and synthesis of novel cationic and anionic surfactants with regularly spaced unsaturation in their hydrophobic hydrocarbon tails and the first application of ring closing metathesis depolymerization to surfactant degradation resulting in the mild, facile decomposition of these new compounds to produce relatively volatile nonsurface active remnants.     

Direction trees

Given a finite set of noncollinear points in the real plane, it is shown that they can be connected to form a tree using lines, no two of which are parallel.