Fine-pitch and thick-foil gas electron multipliers for cosmic x-ray polarimeters

We have produced various gas electron multiplier foils (GEMs) by using laser etching technique for cosmic X-ray polarimeters. The finest structure GEM we have fabricated has 30 μm-diameter holes on a 50 μm-pitch. The effective gain of the GEM reaches around 5000 at the voltage of 570 V between electrodes. The gain is slightly higher than that of the CERN standard GEM with 70 μm-diameter holes on a 140 μm-pitch. We have fabricated GEMs with thickness of 100 μm which has two times thicker than the standard GEM. The effective gain of the thick-foil GEM is 104 at the applied voltage of 350 V per 50 μm of thickness. The gain is about two orders higher than that of the standard GEM. The remarkable characteristic of the thick-foil GEM is that the effective gain at the beginning of micro-discharge is quite improved. For fabricating the thick-foil GEMs, we have employed new material, liquid crystal polymer (LCP) which has little moisture absorption rate, as an insulator layer instead of polyimide. One of the thick-foil GEM we have fabricated has 8 μm copper layer in the middle of the 100 μm-thick insulator layer. The metal layer in the middle of the foil works as a field-shaper in the multiplication channels, though it slightly decreases the effective gain

Fine-pitch and thick-foil gas electron multipliers for cosmic x-ray polarimeters

We have produced various gas electron multiplier foils (GEMs) by using laser etching technique for cosmic X-ray polarimeters. The finest structure GEM we have fabricated has 30 μm-diameter holes on a 50 μm-pitch. The effective gain of the GEM reaches around 5000 at the voltage of 570 V between electrodes. The gain is slightly higher than that of the CERN standard GEM with 70 μm-diameter holes on a 140 μm-pitch. We have fabricated GEMs with thickness of 100 μm which has two times thicker than the standard GEM. The effective gain of the thick-foil GEM is 104 at the applied voltage of 350 V per 50 μm of thickness. The gain is about two orders higher than that of the standard GEM. The remarkable characteristic of the thick-foil GEM is that the effective gain at the beginning of micro-discharge is quite improved. For fabricating the thick-foil GEMs, we have employed new material, liquid crystal polymer (LCP) which has little moisture absorption rate, as an insulator layer instead of polyimide. One of the thick-foil GEM we have fabricated has 8 μm copper layer in the middle of the 100 μm-thick insulator layer. The metal layer in the middle of the foil works as a field-shaper in the multiplication channels, though it slightly decreases the effective gain

Association of the RNF213 p.R4810K Variant With the Outer Diameter of Cervical Arteries in Patients With Ischemic Stroke

Background We investigated the impact of the p.R4810K variant of RNF213 (ring finger protein 213) gene, a susceptibility gene of moyamoya disease in East Asia, on the outer diameter of cervical parts of carotid and vertebral arteries (VAs). Methods We examined consecutive Japanese patients with ischemic stroke who underwent carotid ultrasonography between 2015 and 2019. Patient background and the carotid ultrasonography‐measured outer diameter of extracranial cervical arteries, including the common carotid artery, internal carotid artery, external carotid artery, and cervical VA, were compared between variant carriers and noncarriers. Outer diameters of each artery were defined as the mean distance from far to near wall adventitia of right and left target arteries using carotid ultrasonography. The average diameter of both cervical portions of common carotid arteries, internal carotid arteries, external carotid arteries, and the dominant side diameter of both cervical VAs were used. Results Of the 617 adult patients (204 women; median age, 74 years) analyzed, 26 (4.2%) carried the RNF213 p.R4810K variant. Variant carriers were significantly younger (P<0.01) and had more frequent steno‐occlusion of the M1 segment of the middle cerebral artery (P<0.01). Multivariate logistic regression analysis showed that variant carriers had significantly smaller mean diameters in the common carotid artery (7.25 versus 8.22 mm; adjusted odds ratio [aOR] per 1 mm decrease, 2.94; 95% CI, 1.69–5.00), cervical internal carotid artery (4.99 versus 5.55 mm; aOR, 1.66; 95% CI, 1.03–2.70), and cervical VA (3.55 versus 4.10 mm; aOR, 2.56; 95% CI, 1.33–4.76) than noncarriers. Mean diameters of the common carotid artery (aOR, 3.44; 95% CI, 2.08–5.88) and cervical internal carotid artery (aOR, 2.04; 95% CI, 1.23–3.33) and the dominant diameter of the cervical VA (aOR, 3.23; 95% CI, 1.72–5.88) were also smaller in variant carriers even when the analysis was restricted to patients without bilateral steno‐occlusion in target vessels or intracranial arteries distal to target vessels. Conclusion RNF213 p.R4810K variant carriers have smaller cervical arterial outer diameters in both anterior and posterior circulations than noncarriers with ischemic stroke. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT02251665

Eur Stroke J

INTRODUCTION: The underlying causes of spontaneous vertebral artery dissection (sVAD) remain insufficiently understood. This study aimed to determine whether high-pillow usage is associated with an increased risk of sVAD and evaluate the frequency of sVAD attributable to high-pillow usage. PATIENTS AND METHODS: This case-control study identified patients with sVAD and age- and sex-matched non-sVAD controls (case-to-control ratio: 1:1) treated at a certified comprehensive stroke center in Japan between 2018 and 2023. The pillow height used at the onset of the index disease was measured and classified into three categories between 12 and 15 cm boundaries. Univariable logistic regression was performed to assess the odds ratio (OR) with a 95% confidence interval (CI) of high-pillow usage for sVAD development. A subgroup of sVAD attributable to high-pillow usage was defined with the following three conditions: high-pillow usage (⩾12 or ⩾15 cm); no minor preceding trauma; and wake-up onset. RESULTS: Fifty-three patients with sVAD and 53 non-sVAD controls (42% women, median age: 49 years) were identified. High-pillow usage (⩾12 and ⩾15 cm) was more common in the sVAD group than in the non-sVAD group (34 vs 15%; OR = 2.89; 95%CI = 1.13-7.43 and 17 vs 1.9%; OR = 10.6; 95%CI = 1.30-87.3, respectively). The subgroup of sVAD attributed to high-pillow usage (⩾12 and ⩾15 cm) was found in 11.3% (95%CI = 2.7%-19.8%) and 9.4% (95%CI = 1.5%-17.3%), respectively. CONCLUSION: High-pillow usage was associated with an increased risk of sVAD and accounted for approximately 10% of all sVAD cases. This tentative subgroup of sVAD may represent a distinct spectrum of disease-Shogun pillow syndrome

Abstract 1122‐000009: Impact of RNF213 p.R4810K Variant on Endovascular Therapy Outcome for Acute Large Vessel Occlusion Stroke

Introduction: The ring finger protein 213 gene (RNF213) has been identified as a susceptibility gene for moyamoya disease, and the p.R4810K polymorphism as a founder variant commonly found in East Asian patients. 1  A recent large case‐control study including over 46,958 Japanese subjects reported that the RNF213 p.R4810K variant was a strong risk factor for Japanese cerebral infarction: the variant was found in 5.2% of patients with non‐cardioembolic stroke and in 2.1% of healthy controls. 2   Mechanical thrombectomy (MT) is a standard treatment for acute ischemic stroke due to occlusion of the internal carotid artery and M1 segment of the middle cerebral artery, but in East Asians, about 15–25% of LVOs for which MT was performed were reportedly caused by intracranial atherosclerotic disease (ICAD). 3  RNF213 p.R4810K variant may be involved to some extent in ICAD‐related LVO of Asian patients undergoing MT. In this study, we aimed to investigate the impact of RNF213 p.R4810K variant on EVT for anterior circulation LVO stroke. Methods: Of the consecutive ischemic stroke patients from 2011 to 2021 seen in our institute, patients who underwent EVT for acute occlusion of the intracranial ICA or M1 segment of MCA and signed a consent form for RNF213 genotyping were included. Outcomes were instant re‐occlusion, final modified Thrombolysis in Cerebral Infarction (mTICI) ≥2b reperfusion, early re‐occlusion, and modified Rankin Scale (mRS) score 0–2 at 90 days. Instant re‐occlusion was defined as occurrence of re‐occlusion during the procedure, whereas early re‐occlusion as re‐occlusion detected on magnetic resonance angiography within 2 weeks after confirmation of successful reperfusion at the end of the procedure. 4 Results: Of the 277 patients (128 women [46.2%]; median age, 76 years) analyzed, 10 (3.6%) patients had the RNF213 p.R4810K variant. The variant carriers were younger (67 years vs. 76 years, P<0.01), more frequently received angioplasty (40.0% vs. 12.0%, P<0.01), and more frequently had intracranial atherosclerotic disease‐related LVO as a cause of acute LVO (70.0% vs. 8.6%, P<0.01) than non‐carriers. The variant carriers showed higher rates of instant re‐occlusion (40.0% vs. 5.6%, P<0.01), but there were no statistically significant inter‐group differences for the final mTICI ≥2b reperfusion rate between carriers and non‐carriers (100.0% vs. 81.6%, P = 0.22). Early re‐occlusion was more frequent in the variant carriers than non‐ carriers (60.0% vs. 0.4%, P<0.01) with no intergroup difference in the rate of repeated EVT (67.7% vs. 100.0%, P = 0.71). There were no statistically significant inter‐group differences for achievement of mRS score 0–2 (60.0% vs. 51.7%, P = 0.75) Conclusions: Both instant and early re‐occlusion were more frequent in the RNF213 p.R4810K variant carriers who had received EVT for acute anterior circulation LVO than in the non‐carriers. Potential impact of RNF213 polymorphism status on EVT outcomes was clarified

Where Brain, Body and World Collide

The production cross section of electrons from semileptonic decays of beauty hadrons was measured at mid-rapidity (|y| &lt; 0.8) in the transverse momentum range 1 &lt; pt &lt; 8 Gev/c with the ALICE experiment at the CERN LHC in pp collisions at a center of mass energy sqrt{s} = 7 TeV using an integrated luminosity of 2.2 nb^{-1}. Electrons from beauty hadron decays were selected based on the displacement of the decay vertex from the collision vertex. A perturbative QCD calculation agrees with the measurement within uncertainties. The data were extrapolated to the full phase space to determine the total cross section for the production of beauty quark-antiquark pairs

Impact of the RNF213 p.R4810K Variant on Endovascular Therapy for Large‐Vessel Occlusion Stroke

Background We investigated the impact of the ring finger protein 213 p.R4810K variant, a founder variant for moyamoya disease in East Asians, on endovascular therapy outcomes in patients with acute anterior‐circulation large‐vessel occlusion stroke in comparison with noncarriers. Methods Of the consecutive patients with ischemic stroke admitted to our institute from 2011 to 2021, patients who underwent endovascular therapy for acute occlusion of the intracranial internal carotid artery or M1 segment of the middle cerebral artery were included. Outcomes were instant reocclusion, final modified Thrombolysis in Cerebral Infarction reperfusion ≥2b, and early reocclusion. Instant reocclusion was defined as the occurrence of reocclusion during the procedure, and early reocclusion was defined as reocclusion detected on magnetic resonance angiography within 2 weeks after the confirmation of successful reperfusion. Results Of the 277 patients analyzed (128 women; median age, 76 years), 10 patients (3.6%) carried the ring finger protein 213 p.R4810K variant. Variant carriers were younger (P=0.01) and more frequently had intracranial atherosclerotic disease‐related large‐vessel occlusion as a cause of acute large‐vessel occlusion (P<0.001) compared with noncarriers. Variant carriers showed a higher rate of instant reocclusion (70.0% versus 5.6%; P<0.001), but there were no significant intergroup differences in the final modified Thrombolysis in Cerebral Infarction ≥2b reperfusion rate between carriers and noncarriers (100.0% versus 81.6%, respectively; P=0.22). Early reocclusion was more frequent in variant carriers compared with noncarriers (60.0% versus 0.4%; P<0.001). Conclusions Instant and early reocclusions were more frequent in variant carriers who underwent endovascular therapy for acute anterior‐circulation large‐vessel occlusion compared with noncarriers