Tohoku University

About: Tohoku University is a education organization based out in Sendai, Japan. It is known for research contribution in the topics: Magnetization & Alloy. The organization has 72116 authors who have published 170791 publications receiving 3941714 citations. The organization is also known as: Tōhoku daigaku.

Cerebrospinal Fluid Tau and β-Amyloid: How Well Do These Biomarkers Reflect Autopsy-Confirmed Dementia Diagnoses?

Abstract: Background Tau and β-amyloid (Aβ) are proposed diagnostic biomarkers for Alzheimer disease (AD). Previous studies report their relationship to clinical diagnoses of AD and other dementias. To understand their value as predictors of disease-specific patholody, levels determined during life must be correlated with definitive diagnoses in mixed dementia groups and cognitively normal subjects. Objectives To correlate antemortem cerebrospinal fluid (CSF) tau and Aβ levels with definitive dementia diagnosis in a diverse group of patients; to calculate statistics for CSF tau and Aβ. Design Prospective study. Setting Ten clinics experienced in the diagnosis of neurodegenerative dementias. Patients One hundred six patients with dementia and 4 cognitively normal subjects with a definitive diagnosis, and 69 clinically diagnosed cognitively normal subjects. Main Outcome Measures Correlation of CSF tau and Aβ with final diagnosis. Results Mean tau level was 612 pg/mL for the 74 patients with AD, 272 pg/mL for 10 patients with frontal dementia, 282 pg/mL for 3 patients with dementia with Lewy bodies, and 140 pg/mL for 73 cognitively normal control subjects. Tau was less than 334 pg/mL for 20 patients with AD. Aβ 42 was reduced in patients with AD (61 fmol/mL) compared with patients with frontal dementia (133 fmol/mL) and control subjects (109 fmol/mL), but not compared with patients with dementia with Lewy bodies (14 fmol/mL) or prion disease (60 fmol/mL). Conclusions Elevated CSF tau levels are associated with AD pathology and can help discriminate AD from other dementing disorders. However, some patients with AD have a level less than the mean ± 2 SDs of the cognitively normal cohort.

Electronic nematicity above the structural and superconducting transition in BaFe2(As1-xPx)2

Abstract: Electronic nematicity, a unidirectional self-organized state that breaks the rotational symmetry of the underlying lattice, has been observed in an iron-based superconductor, BaFe2(As1−xP x )2, over a wide range of phosphorus concentration, resulting in a phase diagram similar to the pseudogap phase diagram of the copper oxides. Electron nematicity, a unidirectional self-organized state that breaks the rotational symmetry of the underlying lattice, has been observed in the iron pnictide and copper oxide high-temperature superconductors, but whether it can exist above the structural transition temperature (Ts) without an external driving force was not known. Kasahara et al. report magnetic torque measurements in the iron pnictide superconductor BaFe2(As1–xPx)2 showing that the nematicity develops well above Ts and persists to the nonmagnetic superconducting regime, resulting in a phase diagram similar to the pseudogap phase diagram of the copper oxides. The authors identify two distinct temperatures — one at T*, signifying a true nematic transition, and the other at Ts (less than T*) — which they show is not a true phase transition, but rather a 'meta-nematic' transition. Electronic nematicity, a unidirectional self-organized state that breaks the rotational symmetry of the underlying lattice1,2, has been observed in the iron pnictide3,4,5,6,7 and copper oxide8,9,10,11 high-temperature superconductors. Whether nematicity plays an equally important role in these two systems is highly controversial. In iron pnictides, the nematicity has usually been associated with the tetragonal-to-orthorhombic structural transition at temperature Ts. Although recent experiments3,4,5,6,7 have provided hints of nematicity, they were performed either in the low-temperature orthorhombic phase3,5 or in the tetragonal phase under uniaxial strain4,6,7, both of which break the 90° rotational C4 symmetry. Therefore, the question remains open whether the nematicity can exist above Ts without an external driving force. Here we report magnetic torque measurements of the isovalent-doping system BaFe2(As1−xP x )2, showing that the nematicity develops well above Ts and, moreover, persists to the non-magnetic superconducting regime, resulting in a phase diagram similar to the pseudogap phase diagram of the copper oxides8,12. By combining these results with synchrotron X-ray measurements, we identify two distinct temperatures—one at T*, signifying a true nematic transition, and the other at Ts (