We report the case of a term neonate with severe fetal bradycardia with an unusually benign clinical course with follow-up till infancy.

We prove that a ring R is an $n \times n$ matrix ring (that is, $R \cong \mathbb {M}_n(S)$ for some ring S) if and only if there exists a (von Neumann) regular element x in R such that $l_R(x) = R{x^{n-1}}$ . As applications, we prove some new results, strengthen some known results and provide easier proofs of other results. For instance, we prove that if a ring R has elements x and y such that $x^n = 0$ , $Rx+Ry = R$ and $Ry \cap l_{R}(x^{n-1}) = 0$ , then R is an $n \times n$ matrix ring. This improves a result of Fuchs [‘A characterisation result for matrix rings’, Bull. Aust. Math. Soc. 43 (1991), 265–267] where it is proved assuming further that the element y is nilpotent of index two and $x+y$ is a unit. For an ideal I of a ring R, we prove that the ring $(\begin {smallmatrix} R & I \\ R & R \end {smallmatrix})$ is a $2 \times 2$ matrix ring if and only if $R/I$ is so.

Background: Trials of endovascular thrombectomy (EVT) for acute stroke have excluded patients with pre-morbid disability. We performed a meta-analysis to assess the effectiveness and safety of EVT in patients with pre-morbid disability. Methods: According to PRISMA guidelines, we searched for studies describing outcomes in patients with pre-morbid disability (modified Rankin Scale [mRS] 2-5), treated with EVT or medical management (MM). Random-effects meta-analysis was used to pool outcomes including return to baseline mRS at 90 days, symptomatic ICH (sICH), and 90-day mortality. Results: We analyzed 14 studies of patients with pre-morbid disability (mRS2-5: EVT=1,373, MM=253). Compared to medical therapy, EVT was associated with higher likelihood of return to baseline mRS (OR=2.37, 95%CI:1.39-4.04) and a trend towards lower mortality (OR=0.68, 95%CI:0.46-1.02), with similar odds of sICH (OR 1.01, 95%CI:0.49-2.08). In studies comparing patients with vs. without pre-morbid disability treated with EVT, similar results were found except that pre-morbid disability, when defined more strictly as mRS 3-5, was associated with mortality (OR 3.49, p<0.001). Conclusions: In patients with pre-morbid disability, EVT carries a higher chance of return to baseline mRS compared to patients treated with MM or without pre-morbid disability, although with higher mortality than patients without pre-morbid disability. These findings merit validation with randomized controlled trials.

Mathematical models are essential to analyze and understand the dynamics of complex systems. Recently, data-driven methodologies have gotten a lot of attention which is leveraged by advancements in sensor technology. However, the quality of obtained data plays a vital role in learning a good and reliable model. Therefore, in this paper, we propose an efficient heuristic methodology to collect data both in the frequency domain and the time domain, aiming at having more information gained from limited experimental data than equidistant points. In the frequency domain, the interpolation points are restricted to the imaginary axis as the transfer function can be estimated easily on the imaginary axis. The efficiency of the proposed methodology is illustrated by means of several examples, and its robustness in the presence of noisy data is shown.

In this work, a low profile ultra-wideband (UWB) antenna is designed and investigated using a novel loop-based wideband artificial magnetic conductor (WB-AMC) for gain enhancement. Initially, a compact loop antenna is designed using stub loading and further optimized for the UWB range by applying curve ground methodology. The average gain of the proposed antenna without WB-AMC is 2.7 dBi. To enhance the gain of the entire UWB range, loop-based WB-AMC in [2 × 2] forms is integrated. WB-AMC is used as a ground plane beneath the antenna. To validate the performance, the UWB antenna and WB-AMC are fabricated and tested. The measured results confirm the entire UWB range. Proposed antenna provides a peak gain of 9.4 dBi and an average gain of 5.8 dBi. Vertical profile reduction of 50% is achieved compared to perfect electric conductor ground. The proposed UWB antenna is a potential candidate for UWB wireless applications due to its attractive features such as low profile, wide bandwidth coverage, omnidirectional pattern, constant high gain, and group delay.

Background: Some patients do poorly despite small infarcts after endovascular therapy(EVT) whilst others with large infarcts do well. We validated exploratory findings from the ESCAPE trial regarding factors associated with such discrepancies, in the ESCAPE-NA1 trial(NCT02930018). Methods: We identified “discrepant cases” with modified Rankin Scale(mRS)≥3 despite small follow-up infarct volume(FIV≤25th-percentile) on 24-hour CT/MRI or mRS≤2 despite large FIV(volume≥75th-percentile). We compared area-under-the-curve(AUC) of pre-specified logistic models containing (a)pre-treatment factors(age/cancer/vascular risk-factors) and (b)treatment-related/post-treatment factors(serious adverse events/SAEs) in identifying small-FIV/mRS≥3 and large-FIV/mRS≤2, with stepwise regression-derived models. Results: Among 1,091 patients, 42/287(14.6%) with FIV≤7mL(25th-percentile) had mRS≥3; 65/275(23.6%) with FIV≥92mL(75th-percentile) had mRS≤2. Pre-specified pre-treatment factors(age/cancer/vascular risk-factors) were associated with FIV≤7mL/mRS≥3; stepwise models selected similar variables(similar AUCs:0.92-0.93,p=0.42). SAEs(infarct-in-new-territory/recurrent stroke/pneumonia/heart failure) were strongly associated with FIV≤7mL/mRS≥3; stepwise models also identified onset-to-needle time and hemoglobin(24-hours) as treatment-related/post-treatment factors(similar AUCs:0.92-0.94,p=0.14). Younger age was associated with FIV≥92mL/mRS≤2; stepwise models also selected diabetes absence and baseline hemoglobin(similar AUCs:0.76-0.77,p=0.82). Absence of SAEs(stroke progression/pneumonia/intracerebral hemorrhage) was strongly associated with FIV≥92mL/mRS≤2; stepwise models also identified 24-hour hemoglobin, glucose, and BP(similar AUCs:0.79-0.80,p=0.030). Conclusions: FIV-mRS discrepancies are associated with pre-treatment factors like age/comorbidities; and post-treatment complications related to stroke evolution, secondary prevention, and post-acute care quality. Optimizing thrombolysis speed, BP, glucose, and hemoglobin are modifiable factors meriting further study.

Background: There are no recommendations regarding endovascular treatment (EVT) for patients with acute ischemic stroke (AIS) due to primary medium vessel occlusion (MeVO). The aim of this study was to examine the willingness to perform EVT among stroke physicians in patients with mild, yet personally-disabling deficits due to MeVO. Methods: In an international survey consisting of 4 cases of primary MeVOs, participants were asked whether the presence of personally-disabling deficits would influence their decision-making for EVT despite the patients having low NIHSS scores. Decision rates were calculated based on physician characteristics. Clustered univariable logistic regression was performed. Results: 366 participants from 44 countries provided 2562 answers. 56.9% opted to perform EVT in scenarios in which the deficit was relevant to the patient’s profession versus 41.0% in which no information regarding patient profession was provided (RR1.39, p<0.001). The largest effect sizes were seen for female participants (RR1.68, 95%CI:1.35-2.09), participants >60 years (RR1.61, 95%CI:1.23-2.10), with more neurointervention experience (RR1.60, 95%CI:1.24-2.06), and who personally performed >100 EVTs per year (RR1.63, 95%CI:1.22-2.17). Conclusions: The presence of a patient-relevant deficit in low NIHSS AIS due to MeVO is an important factor for EVT decision-making. This may have relevance for the conduct and interpretation of low NIHSS EVT randomized trials.

Background: Thrombus embolization during endovascular treatment (EVT) occurs in up to 9% of cases, making secondary medium-vessel occlusions (MeVOs) of particular interest to neurointerventionalists. We sought to gain insight into the current EVT approaches for secondary MeVO stroke in an international case-based survey as there are currently no clear recommendations for EVT in these patients. Methods: Participants were presented with three secondary MeVO cases, each consisting of three case-vignettes with changes in patient neurological status (improvement, no change, unable to assess). Clustered multivariable logistic regression analyses were used to assess factors influencing the decision to treat. Results: 366 physicians from 44 countries took part. The majority (54.1%) were in favor of EVT. Participants were more likely to treat occlusions in the anterior M2/3 (74.3%; risk ratio [RR]2.62, 95%CI:2.27-3.03) or A3 (59.7%; RR2.11, 95%CI:1.83-2.42) segment, compared to the M3/4 segment (28.3%;reference). Physicians were less likely to pursue EVT in patients with neurological improvement (49.9% versus 57.0%; RR0.88, 95%CI:0.83-0.92). Interventionalists and more experienced physicians were more likely to treat secondary MeVOs. Conclusions: Physician’s willingness to treat secondary MeVOs endovascularly is limited and varies per occlusion location and change in neurological status. More evidence on the safety and efficacy of EVT for secondary MeVO stroke is needed.