Search

A total of 1074 patients with a history of ischemic stroke enrolled in The Recurrent Stroke Prevention Clinical Outcome (RESPECT) Study were assigned to intensive blood pressure (BP) control group (blood pressure < 120/80 mmHg) or standard blood pressure control group (blood pressure < 140/90 mmHg) and were followed up for a mean of 3.9 years. Seventy-eight first recurrent strokes occurred, including 70 ischemic stroke and 8 intracerebral hemorrhage. Intensive treatment did not change annual risk of ischemic stroke (1.74% vs. 1.75%, P = 0.999), but markedly reduced risk of hemorrhagic stroke (0.00% vs. 0.39%, P = 0.005). Beneficial effect of intensive BP control were observed for risk of hemorrhagic stroke in the patients with a history of ischemic stroke.

Monomer sequence transformation and reversible polymerization–depolymerization control were achieved in the cationic copolymerization of 2-methyl-1,3-dioxepane and γ-butyrolactone by vacuuming or temperature change. The removal of monomers from the polymerization solution with a vacuum pump promoted depolymerization, resulting in a transformation to pseudo-alternating copolymers and subsequent oligomer formation. Heating the polymerization solution also promoted a similar monomer sequence transformation and oligomer formation, while cooling led to the polymerization of monomer molecules generated via depolymerization.

Our recent results in the concurrent cationic vinyl-addition and ring-opening copolymerization of vinyl ethers (VEs) and oxiranes are summarized with particular emphasis on the strategies required to generate crossover reactions between different types of monomers. Most importantly, carbocation generation via the ring-opening reaction of the oxonium ion is indispensable for the crossover reaction from oxirane to VE. This article also summarizes concurrent cationic vinyl-addition, ring-opening and carbonyl-addition terpolymerization, the copolymerization using an alkoxyoxirane through the alkoxy group transfer mechanism and the long-lived species-mediated polymerization using cyclic formals.

An initiating system composed of GaCl₃ and an alkylbenzene was demonstrated to be highly effective for the controlled cationic polymerization of a plant-derived monomer, β-pinene. When two equivalents of hexamethylbenzene were added to GaCl₃ in conjunction with 2-chloro-2,4,4-trimethylpentane as an initiator, cationic polymerization of β-pinene successfully proceeded in a living manner at –78 °C. Successful control over the reaction was attributed to the formation of a complex between GaCl₃ and the alkylbenzene, as confirmed by UV–vis and ⁷¹Ga NMR analyses.

Cationic polymerization of p-methylstyrene (pMeSt) was examined using various metal chlorides as Lewis acid catalysts in dichloromethane. Polymerization using SnCl₄ and ZnCl₂ in conjunction with 2,6-di-tert-butylpyridine (DTBP) proceeded in a controlled manner in contrast to the reactions with metal trichlorides, including AlCl₃, FeCl₃ and GaCl₃. In addition, the combination of SnCl₄ and DTBP allowed the controlled polymerization of less reactive styrenes and the synthesis of star-shaped poly(pMeSt)s through the cross-linking reaction using an alkylstyrene-type divinyl compound.