Microporous nanocomposites of Pd and Au nanoparticles via hierarchical self-assembly

Microporous nanocomposites of Pd and Au nanoparticles were generated by utilizing electrostatic interaction between oppositely charged Au nanoparticles coated with carboxylate groups (Au-COO-) and spherical aggregates of Pd nanoparticles (Pd- NH3+) with a mean diameter of 80+/-20 nm stabilized and cross linked by octa(aminopropyl)silsesquioxane octahydrochloride (POSS-NH3+). Amide bonds were formed between the reactive ion couples that are well defined in the Pd-Au colloidal nanocomposites during a subsequent chemical reaction to generate more stable nanocomposites with improved chemical and physical properties.

Photochemical assembly of gold nanoparticles utilizing the photodimerization of thymine

Irradiation of UV light to the solution of gold nanoparticles modified with thymine units resulted in the formation of aggregates comprising chemical cross-linking gold nanoparticles through the photodimerization of the thymine units. Transmission electron microscopy and UV-visible absorption measurement showed the aggregates consisting of the gold nanoparticles. The effect of thymine unit density on the nanoparticle surface and the concentration of the gold nanoparticles in solution to the aggregation process were studied by UV-visible absorption measurement.

Synthesis of Gold Nanoparticles Modified with Ionic Liquid Based on the Imidazolium Cation

The synthesis and processing of nanoparticles consisting of metallic nanocrystal cores and organic monolayer shells promise interesting technological applications. Here, we report the synthesis of gold nanoparticles modified with ionic liquids based on the imidazolium cation. Aggregation-induced color changes of the gold nanoparticles in an aqueous solution were used as an optical sensor for anions via anion exchange of ionic liquid moiety. We also demonstrated the phase transfer of the gold nanoparticles from aqueous media to ionic liquid.

Effects of delayed (24 h postintervention) β-irradiation therapy after coronary angioplasty and stenting in de novo native coronary artery lesions

BACKGROUND

The effects of brachytherapy performed 24 h postintervention in de novo native coronary artery lesions.

METHODS AND RESULTS

Thirty-nine patients with 39 de novo coronary artery lesions were randomised to prompt (immediately after intervention, n=21) or delayed (24 h later, n=18) beta brachytherapy ((90)Sr/(90)Y) after been successfully revascularized with stenting. Clinical follow-up data up to 21 months (median time) were compared. After irradiation and at 6-month follow-up, paired volumetric analysis of the stented segment and the 5-mm proximal and distal reference segments was performed; this included measurements of the external elastic membrane, lumen, plaque, and media (external elastic membrane minus lumen), stent and intima hyperplasia (stent minus lumen). Baseline clinical and angiographic characteristics were similar in the two groups. Postintervention measurements of stent, lumen, and intima hyperplasia volumes as well as postintervention minimum lumen cross-sectional areas were not different. In the stented segments and in the segments 5 mm proximal and distal to the stent, similar changes of all IVUS measurements were measured in the two patient groups, but in the lumen volume at the proximal stent edge of patients irradiated 24 h postinjury. At 21 months median follow-up time, target lesion revascularization (TLR) was performed in 8 patients (38%) in the prompt irradiation group compared with 3 (17%) in the delayed (P=.17).

CONCLUSION

Beta irradiation is similarly effective whether performed immediately after percutaneous coronary intervention or 24 h later.