Kyushu University

About: Kyushu University is a education organization based out in Fukuoka, Japan. It is known for research contribution in the topics: Population & Catalysis. The organization has 68284 authors who have published 135190 publications receiving 3055928 citations. The organization is also known as: Kyūshū Daigaku.

Incidence and risk factors for subtypes of cerebral infarction in a general population: the Hisayama study.

Abstract: Background and Purpose—We estimated the incidence of first-ever cerebral infarction in regard to its subtypes and analyzed their risk factors separately in a community-based prospective cohort study in Japan. Methods—Stroke-free subjects (n=1621) aged ≥40 years were followed up for 32 years from 1961. During this period, 298 cerebral infarctions occurred and were divided into 167 lacunar, 62 atherothrombotic, 56 cardioembolic, and 13 undetermined subtypes of infarction on the basis of clinical information including brain imaging and autopsy findings. Results—The age-adjusted incidence of lacunar infarction (3.8 per 1000 person-years for men and 2.0 for women) was higher than that of atherothrombotic infarction (1.2, 0.7) and cardioembolic infarction (1.3, 0.5) in both sexes. Time-dependent Cox’s proportional hazard analysis revealed systolic blood pressure as well as age to be independent risk factors for all subtypes of cerebral infarction except for cardioembolic infarction in men. Additionally, ST depr...

Highly efficient organic light-emitting diode based on a hidden thermally activated delayed fluorescence channel in a heptazine derivative

Abstract: Considerable progress in organic light-emitting diodes (OLEDs) has triggered intensive effort to develop efficient solid-state electroluminescent (EL) materials over the past two decades. Among the many classes of materials being investigated, transition metal complexes are highly attractive because phosphorescent OLEDs containing Ir (III), Pt (II) and Os (II) complexes exhibit very high external quantum efficiencies (ηext). This is because such complexes effectively harvest triplet excitons, so their efficiencies are four times higher than that of conventional fluorescent OLEDs. However, phosphorescent OLEDs containing transition metal-based compounds are rather expensive and unsustainable because they contain rare metals. While OLEDs containing Cu (I) complexes that exhibit high ηext comparable to those with transition metal complexes have been examined as an alternative, the relatively low reliability and high driving voltage of such OLED are fundamental problems. Therefore, a novel way to realize high EL efficiency is required. Although fluorescent OLEDs have been assumed to show limited efficiency because of the branching ratio of singlet and triplet excitons of 1:3, the most recent fluorescence-based OLEDs have overcome this limitation using triplet-triplet annihilation and thermally activated delayed fluorescence (TADF) [1-2]. In particular, we have developed promising blue and green TADF materials [3-4]. However, the design of efficient orange or red emitters is inherently difficult because the photoluminescence (PL) quantum efficiency tends to decrease as the emission wavelength increases according to the energy gap law.

Total Oxidation of Hydrocarbons on Perovskite Oxides

Abstract: Perovskite-type oxides containing transition metals are attracting great attention as catalysts for complete oxidation of hydrocarbons as well as electrochemical reduction of oxygen (1). A s far as I know, the use of perovskite-type oxides as catalysts was first reported by Meadowcroft in 1970 (2) for the electrochemical reduction of oxygen. Soon after that, Voorhoeve et al. (3) reported the high catalytic activity of perovskite oxides for heterogeneous oxidation. These studies triggered many studies thereafter which are related to exhaust control catalysts and electrode catalysts.