Stroke incidence and usage rate of thrombolysis in a Japanese urban city: the Kurashiki stroke registry.

BACKGROUND: To investigate stroke incidence and rate of thrombolytic therapy in an urban city of around 500,000 residents. METHODS: Patients suffering acute stroke in Kurashiki City (population 474,415) between March 2009 and February 2010 (inclusive) and admitted to 1 of 10 hospitals throughout the city were prospectively enrolled. RESULTS: We enrolled patients with first-ever stroke (n = 763; men 415; median age 72 years) and first-ever/recurrent stroke (n = 1009; men 552; median age 73 years). Among first-ever strokes, 68% were cerebral infarctions, 23% were intracerebral hemorrhages, and 8% were subarachnoid hemorrhages. Crude incidences for first-ever stroke per 100,000 residents were 159.8 (95% confidence interval [CI] 148.4-171.1) for all strokes, 108.8 (95% CI 99.4-118.1) for cerebral infarction, and 36.5 (95% CI 31.0-41.9) for intracerebral hemorrhage. After adjustment using the world population model, age-adjusted incidences were 60.7 (95% CI 45.4-75.9) for all strokes, 38.4 (95% CI 26.3-50.5) for cerebral infarction, and 16.1 (95% CI 8.3-24.0) for intracerebral hemorrhage. Among 698 cases with first-ever and recurrent cerebral infarction, thrombolysis was administered for 31 (5%). Of 197 cerebral infarction patients admitted within 3 hours of onset, the thrombolysis rate was 16%. CONCLUSION: In this urban Japanese city, the age-adjusted incidence of first-ever stroke between March 2009 and February 2010 was 60.7 per 100,000 residents, which was relatively low compared with findings for other countries. Thrombolysis was given to approximately 5% of patients with acute ischemic stroke.

Ferroelectricity from iron valence ordering in the charge-frustrated system LuFe2O4.

Ferroelectric materials are widely used in modern electric devices such as memory elements, filtering devices and high-performance insulators. Ferroelectric crystals have a spontaneous electric polarization arising from the coherent arrangement of electric dipoles (specifically, a polar displacement of anions and cations). First-principles calculations and electron density analysis of ferroelectric materials have revealed that the covalent bond between the anions and cations, or the orbital hybridization of electrons on both ions, plays a key role in establishing the dipolar arrangement. However, an alternative model-electronic ferroelectricity-has been proposed in which the electric dipole depends on electron correlations, rather than the covalency. This would offer the attractive possibility of ferroelectric materials that could be controlled by the charge, spin and orbital degrees of freedom of the electron. Here we report experimental evidence for ferroelectricity arising from electron correlations in the triangular mixed valence oxide, LuFe(2)O(4). Using resonant X-ray scattering measurements, we determine the ordering of the Fe(2+) and Fe(3+) ions. They form a superstructure that supports an electric polarization consisting of distributed electrons of polar symmetry. The polar ordering arises from the repulsive property of electrons-electron correlations-acting on a frustrated geometry.

Giant multiple caloric effects in charge transition ferrimagnet.

Caloric effects of solids can provide us with innovative refrigeration systems more efficient and environment-friendly than the widely-used conventional vapor-compression cooling systems. Exploring novel caloric materials is challenging but critically important in developing future technologies. Here we discovered that the quadruple perovskite structure ferrimagnet BiCu3Cr4O12 shows large multiple caloric effects at the first-order charge transition occurring around 190 K. Large latent heat and the corresponding isothermal entropy change, 28.2 J K-1 kg-1, can be utilized by applying both magnetic fields (a magnetocaloric effect) and pressure (a barocaloric effect). Adiabatic temperature changes reach 3.9 K for the 50 kOe magnetic field and 4.8 K for the 4.9 kbar pressure, and thus highly efficient thermal controls are achieved in multiple ways.

Magnetic and dielectric properties of InFe2O4, InFeCuO4, and InGaCuO4.

The magnetic and dielectric properties of InFe2O4, InFeCuO4, and InGaCuO4 have been investigated. All these materials are isostructural with RFe2O4 (R = Y, Ho-Lu), which shows ferroelectricity due to iron-valence ordering. InFe2O4 exhibits ferrimagnetic ordering at T(C) approximately 242 K and a dielectric constant (epsilon) of approximately 10,000 at around room temperature. These properties resemble those of RFe2O4; the origins of the magnetic and dielectric phenomena are likely common in InFe2O4 and RFe2O4. From measurements of the other two materials, we found that both T(C) and epsilon are decreased in the order of InFe2O4, InFeCuO4, and InGaCuO4. This result strongly supports the previously reported explanation based on an electron transfer between the Fe-site ions for the corresponding rare-earth systems. Therefore, we propose that the dielectric properties of the oxides isostructural with RFe2O4 are plausibly governed by electron transfer; this situation is different from that of ordinary ferroelectrics and dielectrics, in which the displacement of cations and anions is important. In addition, InFeCuO4 and InGaCuO4 exhibit large epsilon values (epsilon > approximately 1500). In consideration of this property, we discuss the possible applications of these oxides.