Nanoscale near-field infrared spectroscopic imaging of silica-shell/gold-core and pure silica nanoparticles

Spectroscopic near-field imaging of single silica-shell/Au-core and pure silica nanoparticles deposited on a silicon substrate is performed in the infrared wavelength range (λ = 9–11 μm) using scattering-type scanning near-field optical microscopy (s-SNOM). By tuning the wavelength of the incident light, we have acquired information on the spectral phonon–polariton resonant near-field interactions of the silica-shell/Au-core and pure silica nanoparticles with the probing tip. We made use of the enhanced near-field coupling between the high index Au-core and the probing tip to achieve spectral near-field contrast of the thin silica coating (thickness < 10 nm). Our results show that spectroscopic imaging of thin coating layers and complex core–shell nanoparticles can be directly performed by s-SNOM.     

3-T MR-guided brachytherapy for gynecologic malignancies

Gynecologic malignancies are a leading cause of death in women worldwide. Standard treatment for many primary and recurrent gynecologic cancer cases includes external-beam radiation followed by brachytherapy. Magnetic resonance (MR) imaging is beneficial in diagnostic evaluation, in mapping the tumor location to tailor radiation dose and in monitoring the tumor response to treatment. Initial studies of MR guidance in gynecologic brachytherapy demonstrate the ability to optimize tumor coverage and reduce radiation dose to normal tissues, resulting in improved outcomes for patients.     

ACTION SPECTRA OF THE PHOTOPHOBIC RESPONSE OF BLUE AND RED FORMS OF Blepharisma japonicum

Abstract— When exposed, in the presence of molecular oxygen, to light intensities of the order of3–30 W m^-2, the ciliate Blepharisma japonicum changes its color from red to blue, because of the photooxidation of the photoreceptor pigment, blepharismin, to pxyblepharismin. Both red-and blue-pigmnentes cells show step-up photophobic responses. The action spectra f the light-dependent behaviour of the red and the blue form of Blepharisma have been determined; their structure is very similar to that the photosensing and phototransducing properties of blepharismin are maintained in its photooxidized form. oxyblepharismin.     

Total Synthesis,Characterization, and Conformational Analysis of the Naturally Occurring Hexadecapeptide Integramide A and a Diastereomer

Integramide A is a 16‐amino acid peptide inhibitor of the enzyme HIV‐1 integrase. We have recently reported that the absolute stereochemistries of the dipeptide sequence near the C terminus are L ‐Iva¹⁴‐D ‐Iva¹⁵. Herein, we describe the syntheses of the natural compound and its D ‐Iva¹⁴‐L ‐Iva¹⁵ diastereomer, and the results of their chromatographic/mass spectrometric analyses. We present the conformational analysis of the two compounds and some of their synthetic intermediates of different main‐chain length in the crystal state (by X‐ray diffraction) and in solvents of different polarities (using circular dichroism, FTIR absorption, and 2D NMR techniques). These data shed light on the mechanism of inhibition of HIV‐1 integrase, which is an important target for anti‐HIV therapy.