Light-emitting polymers and their LED devices

Highly luminous polymers have successfully been prepared by copolymerization of various arylene vinylene units. The random copolymerization of the monomers having different energy gaps or conjugation degrees can generate the irregularity in poly(arylene vinylenes) and enhance the fluorescence of the polymer. Among the copolymers synthesized, the m/p-phenylene vinylene copolymer showed fairly strong fluorescence and gave the most efficient polymer light-emitting diode (P-LED) device because of the good balance of the exciton confinement and the charge transporting property. The optimized P-LED device showed a maximum luminance of 70000 cd/m²     

Superselective bronchial arterial infusion therapy with cisplatin and epirubicin hydrochloride, mitomycin C-iohexol-Lipiodol emulsion (EMILE) for hilar lung adenocarcinoma: preliminary clinical experience

A case of hilar lung adenocarcinoma was treated by superselective bronchial arterial infusion therapy with cisplatin and epirubicin hydrochloride, mitomycin C-iohexol-Lipiodol emulsion (EMILE) using Tracker -18 infusion catheter. The tumor size was reduced on follow-up CT scans. However, EMILE was also distributed to nontumorous lung tissues around the tumor, and a shrinkage of the right upper lobe and elevations of the right hilus and diaphragm followed. No major complaints and clinical complications during and after the treatment occurred. This therapy was safe and effective for local tumor reduction in a case of hilar lung adenocarcinoma.     

Elasticity of entangled networks

Entanglements are modelled by links which make a sliding contact between polymer networks. A formal solution to this problem is given using the replica formalism and the contribution of an entanglement to the free energy of shear is given by:

$\text{1}\text{2}\text{kT}\text{∑}\text{i}\text{λ}{}_{\mathrm{i}}{}^2\text{(1+η)}\text{1 + ηλ}{}_{\mathrm{i}}{}^2\text{+ kT∑log(1+ηλ}{}_{\mathrm{i}}{}^2$

where λ_i are the Cartesian extension ratios and η is a measure of the freedom of a link to slide compared with the freedom of movement of a chain. The expression quoted gives correct limits in the (trivial) case of η zero, and η infinity, when it is merely a negative contribution to the osmotic pressure of the network.     

A new microporous polyurethane vascular graft prepared by an excimer laser ablation technique

Three types of polyurethane (PU) based tubes (internal diameter, 2 mm; wall thickness, 100 microns) with micropores of well controlled size and arrangement were fabricated using an excimer laser (KrF) ablation technique. The pore size (100 microns) and the longitudinal pore-to-pore distance (200 microns) were constant, and the circumferential pore-to-pore intervals were 60 degrees (type 1), 30 degrees (type 2), and 15 degrees (type 3). The surface of the fabricated tube was photochemically modified with photoreactive gelatin. Scanning electron microscopy showed that pore size and arrangement were precisely controlled as designed, and that a gelatinous layer thoroughly covered the luminal surface. The stiffness parameter (beta), inversely related to compliance, was determined from the change in external diameter against intraluminal pressure. An increase in the number of pores around the circumference decreased the beta value. The type 1 tubes implanted preliminarily in rats for 4 weeks showed good patency (80%). The combination of excimer laser-directed microporing and photochemical surface processing techniques enabled the development of a novel compliant small caliber vascular graft, which is expected to show enhanced transmural tissue ingrowth in vivo.     

Plasma concentrations and coronary vasodilation after sublingual and intracoronary administration of isosorbide dinitrate

To investigate the relationship between plasma levels and coronary vasodilation after administration of isosorbide dinitrate (ISDN), the plasma concentration and diameters of six segments of the left coronary artery were measured before and after sublingual (SL) ISDN (5 mg) and left intracoronary (IC) administration of ISDN (3 mg) in 12 patients. After SL-ISDN, the systolic aortic pressure decreased with no significant concomitant changes in heart rate or diastolic aortic pressure. After IC-ISDN, all hemodynamic parameters showed significant changes, and these were greater after IC-ISDN than those after SL-ISDN. The individual mean vasodilation of six segments induced by SL- and IC-ISDN, were 23 +/- 9 and 35 +/- 11% (p < 0.01), respectively. Before SL-ISDN, ISDN was not detected in plasma. After SL- and IC-ISDN, however, the plasma values of the ISDN were 36.1 +/- 53.3 and 101.5 +/- 90.0 ng/ml (p < 0.01), respectively. Thus, both coronary vasodilative responses and plasma ISDN levels after IC-ISDN were significantly greater than those after SL-ISDN. However, neither the individual mean coronary vasodilation nor the hemodynamic changes correlated significantly with plasma ISDN levels. Consequently, with administration of the same dose, the coronary vasodilative response to ISDN did not correlate with plasma levels. Furthermore, IC-ISDN dilutes coronary arteries more effectively than SL-ISDN.     

The firing squad synchronization problem for graphs

In this paper, we give a solution of the Firing Squad Synchronization Problem for graphs. The synchronization times of solutions which have been obtained are proportional to the number of nodes of a graph. The synchronization time of our solution is proportional to the radius r_G of a graph (G (3r_G + 1 or 3r_G time units, where r_G, is the longest distance between the general and any other node of G. This synchronization time is minimum for an infinite number of graphs.