A multi-component reaction (MCR) approach to the synthesis of highly diverse polymers with polypeptide-like features

A new strategy for the combinatorial synthesis of new materials has been developed through the consecutive application of an Ugi 4CC reaction and a ring-opening metathesis polymerization (ROMP) reaction. Norbornenyl aldehydes and carboxylic acids could be used in the Ugi MCR to give highly diverse monomers that were converted to the corresponding polymers by exposure to the second-generation Grubbs' catalyst. These polymers have structural features reminiscent of polypeptides and the process could be extended to the preparation of chiral materials.     

Proliferation assessment in breast cancer: a double-staining technique for AgNOR quantification in MIB-1 positive cells especially adapted for image cytometry

There are two ways of measuring the cell proliferation. The first one consists of quantifying the number of cycling cells with the help of antibodies directed against cells either in G1, S, G2 or M phase. The second way is to assess the cell cycle duration by the quantification of AgNOR proteins. Measuring both the features on the same slide represents an attractive way to tackle the proliferating activity of a cell culture or a tumor. Here, we propose a MIB-1 and AgNOR double staining method especially adapted to image cytometry measurement using MIB-1 antibody coupled to FITC in order to avoid the thresholding problems encountered with such a multilabeling technique. We have applied this new method on a series of 39 breast cancer cases, with at least 4 years follow-up, in order to determine the prognosis significance of this measurement. MIB-1 alone is not linked to prognosis, while the global mean AgNOR area is significantly linked to prognosis in terms of development of visceral metastasis or death. However, the global mean AgNOR area is insufficient to determine the time limit of appearance of metastasis or relapse. Our results clearly demonstrate that a high mean AgNOR area within a cell population having a high MIB-1 index can discern tumors with a high metastatic potential. By multiplying AgNOR area by the percentage of MIB-1 positive cells we calculate the proliferative activity, P, which brings very important information concerning the time limit of relapse.     

Ultra fine carbon nitride nanocrystals synthesized by laser ablation in liquid solution

Crystalline carbon nitride nanopowders and nanorods have been successfully synthesized at room temperature and pressure using the novel technique of pulsed laser ablation of a graphite target in liquid ammonia solution. High-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), and Fourier transform infrared spectroscopy (FTIR) were used to systematically study the morphology, nanostructure and chemical bonding. The experimental composition and structure of the nanoparticles are consistent with the theoretical calculations for α-C₃N₄. After 2 h ablation the particles had a size distribution ∼8–12 nm, whereas after 5 h ablation the particles had grown into nanorod-like structures with a crystalline C₃N₄ tip. A formation mechanism for these nanorods is proposed whereby nanoparticles are first synthesized via rapid formation of an embryonic particle, followed by a slow growth, eventually leading to a one-dimensional nanorod structure.     

Infrared facility at the Canadian light source

The Canadian Light Source (CLS) is constructing two beamlines for Infrared Spectroscopy using synchrotron radiation (IRSR). One will supply mid-Infrared (2–25 μ) light to a Fourier Transform Infrared (FTIR) spectrometer and microscope for biological applications. The second will have a high resolution FTIR spectrometer for gas-phase and surface spectroscopy in the far-Infrared (beyond 25 μ). The Infrared beamlines will use dipole bending magnet radiation from a special bend magnet port design which provides a 50 mrad square acceptance. Issues with the first mirror and photon mask design, as well as the beamline layout and features are discussed.     

First natural analogs of the cytotoxic thiodepsipeptide thiocoraline A from a marine Verrucosispora sp

A marine Verrucosispora sp. isolated from the sponge Chondrilla caribensis f. caribensis was found to produce thiocoraline, a potent cytotoxic compound. Five new analogs of thiocoraline were isolated and represent the first analogs of thiocoraline. 22'-Deoxythiocoraline (2), thiochondrilline C (5), and 12'-sulfoxythiocoraline (6) demonstrated significant cytotoxicity against the A549 human cancer cell line with EC(50) values of 0.13, 2.86, and 1.26 μM, respectively. The analogs provide insight into the SAR and biosynthesis of thiocoraline. The DP4 probability method was used to analyze ab initio NMR calculations to confirm stereochemical assignments.     

Oxoneptunium(v) as part of the framework of a polyoxometalate

(NH4)14Na4[(Np3W4O15)(H2O)3(BiW9O33)3].62H2O (1) and (NH4)14.5Na3.5[(Np3W4O15)(H2O)3(SbW9O33)3].40.5H2O (2) each contain three neptunyl(v) moieties encapsulated within heteropolyoxotungstate frameworks in which axial {NpO2}+ oxygens form one face of a WO6 octahedron.     

Synthesis of certain 5-substituted thieno[2,3-b]thiophene-2-sulfonamides and thieno[2,3-b]thiophene-2-sulfonamide 6,6-dioxides

A series of the title compounds were prepared for evaluation as inhibitors of carbonic anhydrase II. Oxidation of 5-substituted thieno[2,3-b]thiophene-2-sulfonamides provided the first examples of thiophene[2,3-b]thiophene-2-sulfonarnide 6,6-dioxides. These cyclic vinyl sulfones readily underwent addi tion to give predominately that 4,5-cis addition product.