Soft X-ray microscopes can be used to examine whole, hydrated cells up to 10 microm thick and produce images approaching 30 nm resolution. Since cells are imaged in the X-ray transmissive "water window", where organic material absorbs approximately an order of magnitude more strongly than water, chemical contrast enhancement agents are not required to view the distribution of cellular structures. Although living specimens cannot be examined, cells can be rapidly frozen at a precise moment in time and examined in a cryostage, revealing information that most closely approximates that in live cells. In this study, we used a transmission X-ray microscope at photon energies just below the oxygen edge (lambda = 2.4 nm) to examine rapidly frozen mouse 3T3 cells and obtained excellent cellular morphology at better than 50 nm lateral resolution. These specimens are extremely stable, enabling multiple exposures with virtually no detectable damage to cell structures. We also show that silver-enhanced, immunogold labelling can be used to localize both cytoplasmic and nuclear proteins in whole, hydrated mammary epithelial cells at better than 50 nm resolution. The future use of X-ray tomography, along with improved zone plate lenses, will enable collection of better resolution (approaching 30 nm), three-dimensional information on the distribution of proteins in cells.

Spirobi(dithienosilole)s were prepared and their optical and FET properties were studied. They showed absorption maxima at 358–368 nm, a little red shifted from those of the corresponding non-spiro type dithienosiloles, indicating that spiro-conjugation operates in these molecules to an extent. The field-effect hole mobility of spirobi[bis(trimethylsilyl)dithienosilole] was determined to be 1.4 × 10−6 cm2 V−1 s−1.

No abstract

No abstract

Synthesis of Novel Spiro-Condensed Dithienosiloles and the Application to Organic FET. -(OHSHITA*, J.; LEE, K.-H.; HAMAMOTO, D.; KUNUGI, Y.; IKADAI, J.; KWAK, Y.-W.; KUNAI, A.; Chem. Lett. 33 (2004) 7, 892-893; Dep. Appl. Chem., Fac. Eng., Hiroshima Univ., Higashi-Hiroshima 739, Japan; Eng.) -M. Paetzel 49-150