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Transitions seen in the electric properties of water-absorbable poly(2,5-benzimidazole) (ABPBI) films were confirmed by electric conductivity, dielectric constant, and time-domain nuclear magnetic resonance (NMR) measurements. The electric resistance of the films was measured at room temperature using a high-resistance meter, and the dielectric constant at room temperature was measured using an LCR meter in the frequency range of 90 Hz to 8 MHz. The water absorption ratio at equilibrium absorption for the films was 37%, which corresponded to a volume fraction of water of 0.33. The electric conductivity of the films without water absorption was ~1014 S·cm−1, and it increased to ~1010 S·cm−1 with increasing volume fraction, showing a percolation threshold at a volume fraction of 0.025, and remarkable transitions at volume fractions of 0.075 and 0.135. The dielectric constant of the films without water absorption was 3.4, and it increased to 8.1 with increasing volume fraction, showing a transition only at a volume fraction of 0.135. Above a volume fraction of 0.075, where a transition in conductivity was observed, there were two relaxation times at 18–31 μs and 20–93 μs, as determined from the time-domain NMR, and these relaxation times increased with increasing volume fraction. The longer relaxation time increased significantly at a volume fraction of 0.072, which was close to the volume fraction of the transition seen in conductivity. The relationship between the chain mobility of ABPBI and the deterioration in electric insulating properties is discussed. [ABSTRACT FROM AUTHOR]

Background: Intravenous alteplase treatment is effective for acute cerebral infarction, irrespective of the stroke type. However, its value for branch atheromatous disease (BAD) remains unclear, and early neurological deterioration (END) can occur. Aim: To investigate factors affecting END after intravenous alteplase treatment in patients with acute BAD. Methods: This study included 40 consecutive patients diagnosed with cerebral infarction due to BAD in the lenticulostriate artery territory and treated with intravenous alteplase between April 2007 and March 2023. END was defined as an increase of ≥2 points in the total National Institutes of Health Stroke Scale score or ≥1 point in the motor items within 24 h post‐alteplase administration compared to the score at admission. Factors affecting END were retrospectively evaluated. Results: END was observed in 17 of the 40 patients (43%). The median time from the start of alteplase administration to the worsening of neurologic symptoms was 5 h. After intravenous alteplase treatment, the END group had a significantly lower 24‐h average systolic blood pressure (SBP, mean ± standard deviation mmHg) than the non‐END group (142.0 ± 15.2 vs. 149.4 ± 12.0, p < 0.001). The SBP at each time point (immediately before alteplase administration and every 2 h up to 24 h after alteplase administration) was significantly lower in the END than in the non‐END group at 2, 4, and 6 h after alteplase administration. Conclusions: When intravenous alteplase was administered for BAD, BP control after alteplase administration affected END. When alteplase is administered for BAD, it is important to control the blood pressure to maintain hemodynamics. [ABSTRACT FROM AUTHOR]

Essential thrombocythemia (ET) is a myeloproliferative neoplasm that is a rare cause of ischemic stroke. We herein report a 70-year-old man with JAK2 V617F mutation-positive ET who experienced ischemic stroke twice in 1 month due to transient stenosis. In both events, transient stenosis formed at the same curvature of the right middle cerebral artery, and the thrombus disappeared with the initiation of antiplatelet agents. The formation of in situ thrombus at the curvature of the intracranial vessels may be a unique characteristic of JAK2 V617F mutation-positive ET patients.

The relationship between the particle mobility and magnetorheological effect was investigated for polyurethane magnetic elastomers containing carbonyl iron particles with various cross-linking densities or plasticizer concentrations. The storage modulus at 0 mT increased and the on-field modulus at 500 mT decreased with the cross-linking density. The critical magnetic field where the storage modulus starts to rise up increased with the cross-linking density, indicating that the movement of magnetic particles is depressed by the cross-linking points of the polyurethane network. Magnetic elastomers with various plasticizer concentrations revealed that the storage modulus at 0 mT decreased and the on-field modulus at 500 mT increased with the plasticizer concentration. The critical magnetic field decreased with increasing plasticizer concentration, indicating that a dense polyurethane network prevents magnetic particles from moving. It was found that the change in the modulus due to the magnetic field can be scaled by the storage modulus at 0 mT as well as the critical magnetic field. Thus, there is a certain correlation between the macroscopic modulus of elasticity (storage modulus at 0 mT) and the microscopic mobility of magnetic particles reflected in the critical magnetic field.

Background: The differences in the characteristics of ischemic stroke associated with a mobile versus nonmobile residual left atrial thrombus (LAT) are unclear. We investigated whether the mobility of an LAT detected by transthoracic echocardiography is associated with the clinical features of stroke., Methods: This study included 20 consecutive patients with nonvalvular atrial fibrillation who were admitted to our hospital for treatment of acute ischemic stroke and then found to have an LAT on transthoracic echocardiography. The patients were divided into two groups: those with a mobile LAT (Group M) and those with a nonmobile LAT (Group N). The clinical, neuroradiological, and echocardiographic variables were assessed., Results: The LAT was mobile in 11 patients (Group M) and nonmobile in nine patients (Group N). The median National Institutes of Health Stroke Scale score on admission was higher in Group M than N (17 vs. 7, respectively; p=0.196). Four patients in Group M and one in Group N developed in-hospital stroke recurrence (36% vs. 11%, respectively; p=0.319). The prevalence of large vessel occlusion (15 events in Group M and 10 events in Group N, including in-hospital recurrent events) was significantly higher in Group M than N (73% vs. 30%, respectively; p=0.049), which seemed to lead to poorer functional outcomes in Group M than N (ratio of modified Rankin scale score of 0-2 at discharge: 18% vs. 44%, respectively; p=0.336)., Conclusions: The mobility of LAT may affect stroke severity in patients with nonvalvular atrial fibrillation.