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In science education, the improvement in students' ability to construct arguments at the primary school level has been reported. Although these studies have identified difficulties in arguments written by primary school students, they do not indicate areas that require improvement in teaching methods. This study aims to explore the possibility of improvement in early primary school students' ability to construct arguments and identify the types of difficulties encountered. Sixty-seven Japanese third-grade students (9-10 years old) were taught to write arguments as specified by Zembal-Saul et al. (2012). The students were given two writing tasks before and after the lesson. To examine the students' written arguments, each component of claim, evidence, and reasoning was scored based on a rubric. On comparing the scores of the pre-test and post-test writing tasks, it was found that 27 out of 67 students still had difficulty writing arguments during the post-test. An analysis of the students' writing revealed four types of difficulties: 'Incompleteness of components', 'Inappropriateness of components', 'Confusion between evidence and reasoning', and 'Confusion between claim and evidence'. This study offers insights pertaining to teaching implications and research recommendations.

This study aimed to improve the dispersion state of single-walled carbon nanotubes (SWCNTs) in a cyclo-olefin polymer (COP) matrix by introducing extensional flow during the compounding through a twin-screw extruder (TSE). A modified mixing element with multiple holes, called a fixed blister disc (XBD), was developed. To describe the mixing performance of XBD, the flow state was characterized via numerical simulation and acquisition of process data such as pressure drop ([DELTA]P) at XBD and specific mechanical energy (SME), while the operational conditions of TSE were varied. The dispersion state of SWCNTs was evaluated from the viewpoint of the melt viscoelastic property, surface resistivity of extruded samples and mechanical properties of injection molded samples. Furthermore, the dispersion morphology was observed via optical microscopy and scanning electron microscopy. As a result, the mixing performance of XBD was improved by increasing the ratio of throughputs Q to screw speed [N.sub.s] (Q/[N.sub.s]) since [DELTA]P, which is related to extensional stress, was increased. However, the trade-off relationship between [DELTA]P and SME was confirmed versus Q/[N.sub.s]. Although the dispersion state at the submicron level was markedly improved with higher SME inputs, higher [DELTA]P reduced the largest agglomerate size and improved dispersion uniformity. Consequently, the mechanical properties were improved significantly. KEYWORDS dispersive mixing, extensional flow, nanocomposite, single-walled carbon nanotube, twinscrew extrusion, 1 | INTRODUCTION The introduction of extensional flow during compounding in a corotating twin-screw extruder (TSE) to improve the dispersion of nanofillers into a polymer matrix has been studied at [...]

Pseudoaneurysm following mechanical thrombectomy (MT) is a rare but possible complication associated with endovascular procedures. This report presents a case of delayed rupture of a pseudoaneurysm after MT with a stent retriever, which was confirmed by open surgery. During hospitalization, an 85-year-old woman had right hemiplegia and aphasia. Magnetic resonance imaging and angiography revealed acute ischemic changes in the left middle cerebral artery because of M2 segment occlusion. MT was performed to address persistent M2 occlusion. Retrieving from distal vessels with the fully deployed Solitaire 4 × 20 mm stent retriever was considered dangerous, we resheathed the stent, but the microcatheter jumped distally. Angiography through microcatheter revealed contrast leakage into the subarachnoid space. The diagnosis was vessel perforation caused by the microcatheter. The lesion was treated with temporary balloon occlusion for 5 minutes using a balloon-guiding catheter, combined with the reversal of heparin anticoagulation by protamine, and a systolic blood pressure reduction to below 120 mm Hg. Anticoagulation was initiated after confirming that postprocedural subarachnoid hemorrhage (SAH) decreased 1 day after the procedure. Fourteen days after the procedure, computed tomography and angiography revealed a massive hematoma with a newly formed small pseudoaneurysm at the site of vessel rupture. Open surgery was performed to close the small artery rupture using a clip. Delayed rupture of the pseudoaneurysm occurred after MT using a stent retriever. If SAH is observed after MT, performing follow-up computed tomography angiography or magnetic resonance angiography is recommended to consider pseudoaneurysm formation. [ABSTRACT FROM AUTHOR]