Solubilisation of [60]fullerenes using block copolymers and evaluation of their photodynamic activities

Unmodified [60]fullerenes (C60) were solubilised with high stability using various type of poly(ethylene glycol) (PEG) based block copolymer micelles. Block copolymer micelle-incorporated C60 fullerenes were studied in cultures for biological activities using human cervical cancer HeLa cells. As a result, the cationic block copolymer micelles delivered C60 into the cells depending on their surface densities and showed cytotoxicity under photoirradiation.     

Induction of cell death by photodynamic therapy with water-soluble lipid-membrane-incorporated [60]fullerene

Intracellular uptake of a lipid-membrane-incorporated C(60) with a cationic surface into HeLa cells was found to induce cell death under visible light irradiation in high efficiency.     

Whispering Gallery Effect in Relativistic Optics

A relativistic laser pulse, confined in a cylindrical-like target, under specific conditions may perform multiple scattering along the internal target surface. This results in the confinement of the laser light, leading to a very efficient interaction. The demonstrated propagation of the laser pulse along the curved surface is just yet another example of the “whispering gallery” effect, although nonideal due to laser–plasma coupling. In the relativistic domain its important feature is a gradual intensity decrease, leading to changes in the interaction conditions. The process may pronounce itself in plenty of physical phenomena, including very efficient electron acceleration and generation of relativistic magnetized plasma structures.     

Enhancement of high energy proton yield with a polystyrene-coated metal target driven by a high-intensity femtosecond laser

We present experimental results on protons accelerated up to 950 keV from a 3-μm thick tantalum foil with a 133-nm thick polystyrene layer on its rear surface, irradiated with a laser pulse having the duration of 70 fs and the intensity of 2.7×10¹⁸ W/cm². The energy distribution of fast protons was measured simultaneously with that of the hot-electrons from the rear surface. The proton yield from the polystyrene-coated target is about 10 times as high as that from the uncoated metal target. This enhancement of the proton yield is roughly proportional to the increase of hydrogen atoms given by the 133-nm thick polystyrene layer, assuming a contaminant layer of ∼10-nm thickness is on the metal surface without coating. This result shows that the polystyrene layer contributes to the yield enhancement. PACS 52.38.Kd; 52.50.Jm; 52.59.-f     

A Convenient Synthesis of Aldehydes from 1,2-Dimethoxyethenyl-Lithium and Trialkylboranes

The reaction of ate-complexes formed from 1,2-dimethoxy-ethenyllithium and trialkylboranes, with BF₃:Et₂O followed by hydrolysis with hydrochloric acid gives the corresponding aldehydes in good yields.     

Non-centrosymmetric coordination polymer with a highly hindered octahedral copper center bridged by mandelate

A novel chiral coordination polymer, [Cu(C(6)H(5)CH(OH)COO)(μ-C(6)H(5)CH(OH)COO)] (1-L and 1-D), was synthesized through a reaction of copper acetate with L-mandelic acid at room temperature. Although previously reported copper mandelate prepared by hydrothermal reaction was a centrosymmetric coordination polymer because of the racemization of mandelic acid, the current coordination polymer shows noncentrosymmetry and a completely different structure from that previously reported. The X-ray crystallography for 1-L revealed that the copper center of the compound showed a highly distorted octahedral structure bridged by a chiral mandelate ligand in the unusual coordination mode to construct a one-dimensional (1D) zigzag chain structure. These 1D chains interdigitated each other to give a layered structure as a result of the formation of multiple aromatic interactions and hydrogen bonds between hydroxyl and carboxylate moieties at mandelate ligands. The coordination polymer 1-L belongs to the noncentrosymmetric space group of C2 to show piezoelectric properties and second harmonic generation (SHG) activity.     

Synthesis of barium titanate/polymer composites from metal alkoxide

Barium titanate (BaTiO₃)/polymer composite was successfully synthesized by methacryltriisopropoxytitanium (MTPT) and barium alkoxide. MTPT undergoes radical polymerization using azobisisobutyronitrile at temperatures from 90 to 150°C. ¹H NMR spectra showed that MTPT reacted with barium alkoxides yielding a complex alkoxide. BaTiO₃ particles/polymer was formed after the polymerization and hydrolysis of the complex alkoxide. The transmission electron microscopic observation revealed that crystalline BaTiO₃ particles of around 3 nm in size were dispersed in the polymer matrix.     

Structural Design of Ionic Conduction Paths in Molecular Crystals for Selective and Enhanced Lithium Ion Conduction

The molecular crystals [Li{N(SO₂CF₃)₂}{C₆H₄(OCH₃)₂}₂] and [Li{N(SO₂CF₃)₂}{C₆F₂H₂(OCH₃)₂}₂] with solid‐state lithium ion conductivity have been synthesized by the addition of two equivalents of 1,2‐dimethoxybenzene or 1,2‐difluoro‐4,5‐dimethoxybenzene to Li{N(SO₂CF₃)₂}, respectively. Single‐crystal X‐ray diffraction analysis revealed the formation of ionic conduction paths with an ordered arrangement of lithium ions in these crystal structures, afforded by the self‐ assembled stacking of molecular‐based channels consisting of N(SO₂CF₃)₂ anion and 1,2‐dimethoxybenzene frameworks as a result of intermolecular aromatic and hydrogen interactions. These compounds show selective lithium ion conductivity as the anions behave as a component unit of the conduction paths. The relationship between the crystal structure and ionic conductivity of the molecular crystals provides a clue to the development of novel solid electrolytes based on molecular crystals showing fast and selective lithium ion conduction.     

An abnormal temperature dependence of alkylpyrazines' retention in reversed-phase liquid chromatography

Retention behaviors of pyrazine and alkylpyrazines on various stationary phases in reversed-phase liquid chromatography were examined. An abnormal temperature effect on the retention of alkylpyrazines with a mobile phase consisting of acetonitrile and water was observed when changing the column temperature. On the other hand, no similar trend was found with a methanol-water mobile phase. For all the columns investigated in this work, the above tendency to the temperature-dependence was consistently observed, suggesting that the abnormal temperature effect on the retention of alkylpyrazines could be mainly induced by an acetonitrile-based mobile phase.     

Probing conformational states of modified helix 69 in 50S ribosomes

The movement of the small ribosomal subunit (30S) relative to the large ribosomal subunit (50S) during translation is widely known, but many molecular details and roles of rRNA and proteins in this process are still undefined, especially in solution models. The functional relationship of modified nucleotides to ribosome activity is one such enigma. To better understand ribosome dynamics and the influence of modified nucleotides on such processes, the focus of this work was helix 69 of 23S rRNA, which contains three pseudouridine residues in its loop region. Ribosome probing experiments with dimethylsulfate revealed that specific base accessibilities and individual nucleotide conformations in helix 69 are influenced differently by pH, temperature, magnesium, and the presence of pseudouridine modifications.