7 research outputs found
Analysis for Stroke Etiology in Duplicated/Accessory MCA-Related Cerebral Infarction: Two Case Report and Brief Literature Review
Duplication and accessory of the middle cerebral artery (MCA) constitute a rare congenital variation. MCA anomalies are found at a lesser frequency than the vascular anomalies of the other major intracranial arteries. Duplicated/accessory MCA was usually noted incidentally with subarachnoid hemorrhage, due to resulted aneurysmal formation. However, duplicated/accessory MCA-related cerebral infarction is rarer. We report two cases of cerebral infarction due to dissection at the entry of the duplicate/accessory MCA. Both cases were similar in dissected site and clinical course, without headache or injury. In 20 previously reported cases and our two cases of duplicated/accessory MCA-related infarction, mean age (55.8 ± 21.2 years) was slightly younger for cerebral infarction, and stroke etiology was mainly embolism. The main etiologies of stroke were embolism and dissection. Considering embolism etiology, proximal site of arterial diameter changing lesion was a common site for embolism, as duplicated/accessory MCA was usually smaller than normal M1 segment. In cerebral dissection cases, the dissected site was similar to our cases. Numerous mechanisms of dissection were considered, but they mainly included dysfunction of the media and endothelium or shearing stress at the entry of duplication. As the detailed mechanisms of cerebral dissection remain unknown, clinicians should include a differential diagnosis for MCA dissection
Analysis for Stroke Etiology in Duplicated/Accessory MCA-Related Cerebral Infarction: Two Case Report and Brief Literature Review
Duplication and accessory of the middle cerebral artery (MCA) constitute a rare congenital variation. MCA anomalies are found at a lesser frequency than the vascular anomalies of the other major intracranial arteries. Duplicated/accessory MCA was usually noted incidentally with subarachnoid hemorrhage, due to resulted aneurysmal formation. However, duplicated/accessory MCA-related cerebral infarction is rarer. We report two cases of cerebral infarction due to dissection at the entry of the duplicate/accessory MCA. Both cases were similar in dissected site and clinical course, without headache or injury. In 20 previously reported cases and our two cases of duplicated/accessory MCA-related infarction, mean age (55.8 ± 21.2 years) was slightly younger for cerebral infarction, and stroke etiology was mainly embolism. The main etiologies of stroke were embolism and dissection. Considering embolism etiology, proximal site of arterial diameter changing lesion was a common site for embolism, as duplicated/accessory MCA was usually smaller than normal M1 segment. In cerebral dissection cases, the dissected site was similar to our cases. Numerous mechanisms of dissection were considered, but they mainly included dysfunction of the media and endothelium or shearing stress at the entry of duplication. As the detailed mechanisms of cerebral dissection remain unknown, clinicians should include a differential diagnosis for MCA dissection
Photoinduced Transient States of Antiferromagnetic Orderings in LaSrFeO and SrFeO Thin Films Observed through Time-resolved Resonant Soft X-ray Scattering
The relationship between the magnetic interaction and photoinduced dynamics
in antiferromagnetic perovskites is investigated in this study. In
LaSrFeO thin films, commensurate spin ordering is
accompanied by charge disproportionation, whereas SrFeO thin films show
incommensurate helical antiferromagnetic spin ordering due to increased
ferromagnetic coupling compared to LaSrFeO. To
understand the photoinduced spin dynamics in these materials, we investigate
the spin ordering through time-resolved resonant soft X-ray scattering. In
LaSrFeO, ultrafast quenching of the magnetic
ordering within 130 fs through a nonthermal process is observed, triggered by
charge transfer between the Fe atoms. We compare this to the photoinduced
dynamics of the helical magnetic ordering of SrFeO. We find that the
change in the magnetic coupling through optically induced charge transfer can
offer an even more efficient channel for spin-order manipulation.Comment: 7 pages, 5 figure
Estimation of the steady-state cyclic electron flux around PSI in spinach leaf discs in white light, CO2-enriched air and other varied conditions
Cyclic electron flux (CEF) around PSI is essential for efficient photosynthesis and aids photoprotection, especially in stressful conditions, but the difficulty in quantifying CEF is non-trivial. The total electron flux through PSI (ETR1) and the linear electron flux (LEFO2) through both photosystems in spinach leaf discs were estimated from the photochemical yield of PSI and the gross oxygen evolution rate, respectively, in CO2-enriched air. Delta Flux = ETR1 - LEFO2 is an upper estimate of CEF. Infiltration of leaf discs with 150 mu M antimycin A did not affect LEFO2, but decreased DFlux 10-fold. Delta Flux was practically negligible below 350 mu mol photons m(-2) s(-1), but increased linearly above it. The following results were obtained at 980 mmol photons m(-2) s(-1). Delta Flux increased 3-fold as the temperature increased from 5 degrees C to 40 degrees C. It did not decline at high temperature, even when LEFO2 decreased. Delta Flux increased by 80% as the relative water content of leaf discs decreased from 100 to 40%, when LEFO2 decreased 2-fold. The method of using Delta Flux as a non-intrusive upper estimate of steady-state CEF in leaf tissue appears reasonable when photorespiration is suppressed