Cleavages along {110} in bcc iron emit dislocations from the curved crack fronts.

Body-centered-cubic (bcc) transition metals, such as [Formula: see text]-Fe and W, cleave along the {100} plane, even though the surface energy is the lowest along the {110} plane. To unravel the mechanism of this odd response, large-scale atomistic simulations of curved cleavage cracks of [Formula: see text]-Fe were conducted in association with stress intensity factor analyses of straight crack fronts using an interatomic potential created by an artificial neural network technique. The study provides novel findings: Dislocations are emitted from the crack fronts along the {110} cleavage plane, and this phenomenon explains why the {100} plane can be the cleavage plane. However, the simple straight crack-front analyses did not yield the same conclusion. It is suggested that atomistic modeling, at sufficiently large scales to capture the inherent complexities of materials using highly accurate potentials, is necessary to correctly predict the mechanical strength. The method adopted in this study is generally applicable to the cleavage problem of bcc transition metals and alloys.

Endovascular Treatment of Cerebral Venous Circulation Dysfunction Caused by Hemodialysis Shunt: A Case Report.

Objective: Central venous disease, defined as ≥50% stenosis or obstruction of central veins, is one of many life-threatening complications faced by patients on hemodialysis. It often presents as upper limb edema to the arteriovenous (AV) shunt for hemodialysis, although neurological symptoms are rare. We report a case of central venous disease with neurological symptoms associated with endovascular therapy. Case Presentation: A 79-year-old man presented with status epilepticus. His past medical history included rectal carcinoma when he was 69 years old and indication for hemodialysis when he was 79 years old. However, he had no history of neurological disease or epilepsy. On arrival at our facility, CT perfusion revealed venous circulation dysfunction on the left cerebral hemisphere. DSA demonstrated regurgitation from the AV shunt on left upper limb to the cerebral veins and obstruction of the left subclavian vein. Ligation of the causal AV shunt was deemed difficult due to surrounding edema; therefore, endovascular transarterial coil embolization was performed. After completely occluding the AV shunt, patient's condition improved significantly. The patient was discharged 3 days later without neurologic symptoms, with no recurrence of epilepsy was observed to date. Conclusion: Coil embolization of causal AV shunt significantly improved the neurological symptoms of central venous disease.

Development of delayed neurologic sequelae in acute carbon monoxide poisoning cases caused by briquette-based kotatsu: A case-control study.

ABSTRACT: Briquette-based kotatsu, a traditional Japanese heating system, is still used in rural areas and has been linked to the development of acute carbon monoxide (CO) poisoning. This study aimed to investigate the occurrence of delayed neurologic sequelae (DNS) in patients with acute CO poisoning caused by briquette-based kotatsu.This retrospective study included 17 patients treated for acute CO poisoning due to briquette-based kotatsu, between April 2017 and March 2020. Patients were divided into either a sequelae group (3 patients) or a non-sequelae group (14 patients) based on the presence or absence, respectively, of DNS. Demographic data, kotatsu characteristics, clinical findings, and therapies were compared between the 2 groups.Significant differences were noted in patient posture during their initial discovery. Specifically, all non-sequelae patients only had their legs under the kotatsu quilt and all sequelae patients had their entire bodies under the kotatsu quilt (P = .001). There were no statistically significant differences in carbon monoxide levels in hemoglobin (CO-Hb) or the creatine-kinase myocardial band (CK-MB), between the 2 groups; however, troponin-I levels were significantly higher in the sequelae group (P = .026). Abnormal head imaging findings were noted in 2 sequelae-group patients, with a significant difference between the groups (P = .025).We speculate that acute CO poisoning, caused by briquette-based kotatsu, may lead to DNS more frequently in patients in who cover their entire body with the kotatsu quilt and are found in this position. Patients should be warned about the dangers of acute CO poisoning when using briquette-based kotatsu.

Hydrogen-accelerated spontaneous microcracking in high-strength aluminium alloys.

Aluminium alloys are re-evaluated as most feasible way to satisfy the industrial needs of light-weight structural materials. However, unlike conventional structural metals such as iron and titanium, aluminium does not have easily accessible secondary phases, which means that aluminium-based alloys cannot be strengthened by harnessing multiple phases. This leaves age hardening as the only feasible strengthening approach. Highly concentrated precipitates generated by age hardening generally play a dominant role in shaping the mechanical properties of aluminium alloys. In such precipitates, it is commonly believed that the coherent interface between the matrix and precipitate does not contribute to crack initiation and embrittlement. Here, we show that this is not the case. We report an unexpected spontaneous fracture process associated with hydrogen embrittlement. The origin of this quasi-cleavage fracture involves hydrogen partitioning, which we comprehensively investigate through experiment, theory and first-principles calculations. Despite completely coherent interface, we show that the aluminium-precipitate interface is a more preferable trap site than void, dislocation and grain boundary. The cohesivity of the interface deteriorates significantly with increasing occupancy, while hydrogen atoms are stably trapped up to an extremely high occupancy over the possible trap site. Our insights indicate that controlling the hydrogen distribution plays a key role to design further high-strength and high-toughness aluminium alloys.

[Paroxysmal Atrial Fibrillation after Percutaneous Thrombectomy on Day 5 of Onset of Cerebral Embolism:A Case Report].

INTRODUCTION: We report a case of embolic stroke with an atypical course after endovascular therapy performed during the subacute stage of progressive stroke, where symptom relapse could not be controlled despite medical treatment. CASE PRESENTATION: An 81-year-old woman developed slight weakness in her left leg and was hospitalized three days after the onset of symptoms. On admission, her consciousness was almost clear and she exhibited left hemiparesis. The computed tomography(CT)and magnetic resonance imaging(MRI)revealed a cerebral infarction in the right caudate head and corona radiata, and CT perfusion showed no difference in the cerebral blood flow. However, three-dimensional computed tomography angiography showed right M1 occlusion. Considering the clinical course of the leg weakness without atrial fibrillation, antiplatelet therapy for atherosclerotic cerebral infarction was administered. Five days after the symptom onset, the left hemiparesis deteriorated. CT and diffusion-weighted MRI showed increasing edema associated with the cerebral infarction, and CTP showed decreased cerebral blood flow in the right middle cerebral artery region. Because angiography revealed an obstruction involving a long lesion with loss of contrast, we suspected an embolic stroke. Endovascular surgery was performed successfully using the Penumbra system. Postoperatively, the hemiparesis resolved and the patient was transferred to the rehabilitation hospital. CONCLUSION: In rare cases, patients with an embolic stroke develop gradual progression of symptoms. To differentiate between cardioembolic stroke and atherosclerotic cerebral infarction in such patients, a follow-up examination of the brain blood flow must be performed, especially when there is a change in symptoms. This may provide useful information for intravascular treatment even in the subacute period.