Single Stroke Research Articles

Online Hydraulic Stiffness Modulation of a Soft Robotic Fish tail for Improved Thrust and Efficiency.

This paper explores online stiffness modulation within a single tail stroke for swimming soft robots. Despite advances in stiffening mechanisms, little attention has been given to dynamically adjusting stiffness in real-time, presenting a challenge in developing mechanisms with the requisite bandwidth to match tail actuation. Achieving an optimal balance between thrust and efficiency in swimming soft robots remains elusive, and the paper addresses this challenge by proposing a novel mechanism for independent stiffness control, leveraging fluid-driven stiffening within a patterned pouch. Inspired by fluidic-driven actuation, this approach exhibits high bandwidth and facilitates significant stiffness changes. We perform experiments to demonstrate how this mechanism enhances both thrust and swimming efficiency. The tail actuation and fluid-driven stiffening can be optimized for a specific combination of thrust and efficiency, tailored to the desired maneuver type. The paper further explores the complex interaction between the soft body and surrounding fluid and provides fluid dynamics insights gained from the vortices created during actuation. Through frequency modulation and online stiffening, the study extends the Pareto front of achievable thrust generation and swimming efficiency.

Prediction of Aphasia Outcome Using Low Frequency Transcranial Magnetic Stimulation in Post-Stroke Non-Fluent Aphasia

Background: Stroke, a global health concern, often leads to language impairment (aphasia). In Egypt, with a high stroke prevalence, aphasia affects a significant number of survivors. Noninvasive techniques like repetitive transcranial magnetic stimulation (rTMS) show promise in rehabilitation. Cultural variations in test results emphasize the need for region-specific considerations in standardized assessments for post-stroke care. Aim of the work: To evaluate the role of low frequency rTMS to speed up the recovery of post-stroke aphasia for a better quality of life. Patients and Methods: This randomized clinical trial investigates the effects of (rTMS) on post-stroke aphasia. Patients with post-stroke non-fluent aphasia were divided into two groups, with one receiving inhibitory rTMS and the other sham sessions. Inclusion criteria involve adults with a single left hemisphere stroke, while exclusion criteria include prior strokes. The study includes comprehensive assessments for aphasia, and depression. The stimulation protocol involves 20 minutes of daily rTMS for ten days, targeting the right inferior frontal gyrus. The study aims to evaluate the rTMS impact on language recovery. Results: The study evaluated low-frequency rTMS for post-stroke aphasia recovery in 30 patients, comparing TMS and sham groups. No significant demographic or cerebrovascular risk factor differences were found. While rTMS group showed improvement in depression, there were no significant differences between TMS and sham groups in aphasia improvement. Conclusion: Low-frequency rTMS demonstrated no significant superiority over sham stimulation in post-stroke aphasia recovery. Both groups exhibited improved depression without notable distinctions.

Evaluation of physiological variables determining time to mortality after stroke-associated pneumonia.

Introduction Stroke-associated pneumonia (SAP) frequently complicates stroke and is associated with significant mortality. Clinicians often use physiological variables within the National Early Warning Score (NEWS) when diagnosing and prescribing antibiotics for SAP, but little is known of its association with mortality. We investigated the relationship of the NEWS 2 score and its components (respiratory rate, heart rate, temperature, oxygen requirement, oxygen saturation and alertness level) prior to antibiotic initiation, with time-to-mortality in SAP. Methods We included patients with SAP (n=389) from a single hyperacute stroke unit. Diagnosis of SAP was made if pneumonia occurred within 7 days of hospital admission. Kaplan-Meier survival curves were generated to assess NEWS 2 parameters influencing survival at pre-defined time periods (1 year and 5 years). The association of these parameters on time-to-mortality were analysed using multivariable Cox regression models to account for a set of pre-specified potential confounders. Results The median age was 80y (71y-87y) and median NIHSS was 7 (IQR 4-17). Mortality within 1 year was 52.4% and 65.8% within 5 years. In the multivariable analyses, time-to-mortality was independently associated with respiratory rate (HR 1.04, 95% CI 1.01 to1.08, p=0.009) and total NEWS 2 score (HR 1.13, 95% CI 1.06 to 1.21, p=<0.001). Conclusions In patients with SAP, higher respiratory rate and total NEWS 2 score prior to antibiotic initiation were independently associated with time-to-mortality. Further studies are warranted to identify potential opportunities for intervention and ultimately guide treatment to improve outcomes in SAP patients.

Futile recanalization after endovascular treatment in acute ischemic stroke with large ischemic core

BackgroundEndovascular therapy (EVT) is the treatment of choice for acute ischemic stroke (AIS) with large vessel occlusion. However, in many patients, successful EVT recanalization does not correspond to a clinical improvement, called futile recanalization (FR). We aimed to identify stroke risk factors and patient characteristics associated with FR in AIS with large core infarct (LCI).MethodsA total of 137 patients with AIS with LCI treated by EVT at a single stroke center were retrospectively included from January 2016 to June 2023. LCI was defined by Diffusion-Weighted Imaging-Alberta Stroke Program Early Computed Tomography Score (DWI-ASPECT) < 6. Patient age, sex, modified Rankin Scale (mRS), National Institutes of Health Stroke Scale (NIHSS), time to treatment, risk factors, and radiologic findings were collected, and potential associations with FR were analyzed. FR was defined as successful reperfusion with modified Thrombolysis in Cerebral Infarction (mTICI) ≥ 2b but without functional independence at 90 days (mRS ≥ 3). A multivariate logistic regression analysis was conducted on the clinical characteristics of patients, based on the presence or absence of FR, and the factors influencing FR.ResultsOf 137 patients, 120 showed successful recanalization (mTICI ≥ 2b). All patients were divided into FR (n = 80) and no FR (n = 40) groups. Older age (odds ratio [OR] 1.052, 95% confidence interval [CI] 1.002–1.105; p = 0.041), the higher the initial NIHSS score (OR 1.181, 95% CI 1.037–1.344; p = 0.012), and prior intravenous plasminogen activator (OR 0.310, 95% CI 0.118–0.813, p = 0.017) were independent influencing factors of FR.ConclusionsThe older age, the higher the initial NIHSS, and not receiving intravenous plasminogen activator were independently associated with FR in AIS with LCI. These factors could identify poor responders to EVT recanalization.

Reaching the cognitive-motor interface: effects of cognitive load on arm choice and motor performance after stroke.

A vexing characteristic of motor disability after stroke is that many individuals fail to use their affected arm effectively despite having the capacity to do so, a phenomenon termed arm nonuse. Based on the hypothesis that nonuse is influenced by the competing cognitive demands of many daily activities, we examined the effects of cognitive load on arm choice and motor performance in individuals with stroke using a novel virtual reality paradigm that mimics the demands of real-life visual search, object selection, and reaching to targets. Twenty individuals with single left or right hemispheric chronic stroke (11 left cerebrovascular accident; 9 right cerebrovascular accident) and 10 age-matched neurotypical participants completed the Virtual Reality Arm Choice task, in which they reached for target objects in an array under varied cognitive demand. To manipulate cognitive demand, we varied the semantic similarity of objects in the reaching space and the presence or absence of a secondary task. The results showed reduced use of the paretic arm under increased demand. Under cognitive load, participants with stroke also showed slower reach initiation, slower movements, increased reach curvature, and increased performance differences between the paretic and non-paretic arms. The arm choice of neurotypical individuals was also modulated under cognitive load. These data indicate that cognitive factors influence arm choice and motor performance in naturalistic reaching tasks in individuals with chronic stroke. Performance decrements under cognitive load may in turn influence reduced paretic arm use during daily activities.

Effect of teleneurology on door-to-needle times for tenecteplase in acute ischemic stroke

IntroductionIntravenous thrombolysis remains the primary treatment for acute ischemic stroke (AIS); however, administration is time sensitive. Teleneurology services have increased in popularity in recent years due to their ability to aid in triaging patients with neurological conditions. Teleneurology services were implemented at this comprehensive stroke center, in August 2023 to aid in streamlining the administration of tenecteplase in AIS patients. Currently, there are no studies assessing whether the implementation of teleneurology services at a comprehensive stroke center influences tenecteplase door-to-needle time. The purpose of this study is to evaluate the difference in door-to-needle times when tenecteplase is administered with versus without a teleneurology consult. MethodsThis was an institutional review board approved, retrospective cohort study conducted at a single comprehensive stroke center. Adult patients who presented to the emergency department between January 1st, 2022 and April 1st, 2023 were included if they received tenecteplase for the treatment of AIS. The primary outcome was door-to-needle time, defined as the moment the patient first enters the door of the emergency department to the moment the IV bolus of fibrinolytic is administered. Secondary outcomes included the proportion of patients with door-to-needle time within 45 min, neurological improvement at 24 h and discharge, and rate of hemorrhagic conversion. ResultsA total of 93 patients were included with 43 patients in the pre-teleneurology group and 50 patients in the post-teleneurology group. Baseline characteristics were comparable between both treatment groups. The median door-to-needle time was significantly reduced in the post-teleneurology group (49 minutes [IQR, 40.0–70.0] preintervention vs. 34.5 minutes [IQR, 23.8–43.0] postintervention, p < 0.01). For secondary outcomes, the post-teleneurology group had more patients with a door-to-needle time within 45 minutes (44.2% vs. 80.0%, p < 0.01). There was no significant difference in early neurological improvement (58.1% vs. 54.0%), neurological improvement at discharge (60.5% vs. 62.0%), or hemorrhagic conversion (7.0% vs. 12.0%). ConclusionAmong patients who received tenecteplase for the treatment of AIS, there was a significant reduction in door-to-needle time with the use of teleneurology services. There was no difference in neurological improvement or rate of hemorrhagic conversion.

Galling-Free Dry Near-Net Forging of Titanium Using Massively Carbon-Supersaturated Tool Steel Dies.

Massively carbon-supersaturated (MCSed) tool steel dies were developed to make galling-free forging products from titanium bar feedstocks in dry conditions without lubricating oils. Two types of tool steel dies were used, SKD11 and ACD56, following the Japanese Industrial Standard (JIS). The plasma-immersion carburizing process was employed to induce massive carbon supersaturation in two kinds of tool steel dies at 673 K for 14.4 ks. A pure titanium bar was upset in a single stroke up to the reduction of thickness of 70% using the MCSed SKD11 die. Very few bulging displacements of the upset bar proved that μ = 0.05 on the contact surface of the MCSed SKD11 die to pure titanium work. Two continuous forging experiments were performed to demonstrate that an in situ lubrication mechanism played a role to prevent the contact surface from galling to titanium works in both laboratory- and industry-scaled forging processes. After precise microstructure analyses of the contact surface, the free-carbon film formed in situ acted as a lubricating tribofilm to reduce friction and adhesive wear in continuous forging processes. The MCSed ACD56 dies were also used to describe the galling-free forging behavior of manufacturing eyeglass frames and to evaluate the surface quality of the finished temples. The applied load was reduced by 30% when using the MCSed ACD56 dies. The average surface roughness of the forged product was also greatly reduced, from 4.12 μm to 0.99 μm, together with a reduction in roughness deviations. High qualification of forged products was preserved together with die life prolongation even in dry manufacturing conditions of the titanium and titanium alloys.

Recurrent Ischemic Stroke and Transient Ischemic Attack: Risk of Single and Multiple Recurrence.

Background/Objectives: Efforts have been made toward primary or secondary stroke or transient ischemic attack (TIA) prevention. However, little attention has been paid to recurrent stroke or TIA. This study investigated risk factors for multiple or single recurrent stroke or TIA. Methods: Data from 3646 patients with ischemic stroke or TIA were obtained from the Korea University Ansan Hospital Stroke Center between March 2014 and December 2021, using the prospective institutional database of the Korea University Stroke Registry. The associations between clinical features and recurrent stroke or TIA were assessed using bivariable and multivariable Cox models. Results: Recurrent stroke or TIA was associated with male sex (adjusted hazard ratio (HR) 1.95, 95% confidence interval (CI) 1.42-2.80), hypertension (HR 1.49, 95% CI 1.00-2.23), diabetes mellitus (HR 1.54, 95% CI 1.13-2.13), an etiologic subtype of transient ischemic attack (HR 1.88, 95% CI 1.09-3.16), white matter changes (HR 1.62, 95% CI 1.05-2.38), and cerebral microbleeds (HR 1.79, 95% CI 1.26-2.59). Multiple recurrent stroke or TIA was associated with male sex (HR 3.86, 95% CI 1.94-11.55), diabetes mellitus (HR 2.40, 95% CI 1.31-4.53), and anemia (HR 4,58, 95% CI 2.31-10.44). Conclusions: Given the risk factor profiles for recurrent stroke or TIA, risks differed among patient subgroups and were based on multiple or single recurrences. It may exert an effect as a prognostic indicator in the high risk of recurrences.

Passive turbulent jet ignition of jet fuel in a rapid compression machine

Turbulent jet ignition is a promising alternative to conventional spark ignition systems to achieve rapid combustion of difficult-to-ignite mixtures. Jet ignition can facilitate combustion of lean mixtures at low pressure and temperature by ejecting hot reacting jets of unburned gases, intermediate species, and combustion products into the main chamber to accelerate overall ignition. These jets ignite the main chamber at multiple locations, reducing the time required for the main chamber charge to be consumed. The focus of this research is to gain an improved fundamental understanding of the turbulent jet ignition process of F-24 and air at low pressure and temperature conditions with lean (φ = 0.5) and stoichiometric (φ = 1.0) mixtures using 3D RANS simulations. A Rapid Compression Machine with pressure transducers in the pre-chamber and main chamber was modeled, and distinct events during the jet ignition process were determined from pressure measurements and their time derivatives of a single compression stroke. By understanding events during the jet ignition process with jet fuel, these results give insight into achieving stable combustion of heavy fuels at low pressure and temperature conditions with high levels of dilution.

ROTEM and von Willebrand Factor in COVID patients presenting with acute ischemic stroke: A case series: ROTEM and von Willebrand Factor in COVID-19 Related Stroke

ObjectivesSARS-CoV-2 (COVID) induces systemic thrombotic complications including acute ischemic stroke. In this case series, we report markers of inflammation, coagulation factors including von Willebrand factor antigen, and rotational thromboelastometry (ROTEM) data. Materials and methodsRetrospective case series of COVID patients seen at a single comprehensive stroke center between 2020–2022. For patients undergoing mechanical thrombectomy (MT), ROTEM data was collected during the procedure and analyzed on ROTEM delta system. ResultsFifteen patients (33.3% female) median age 65-years-old presented with COVID and acute ischemic stroke. Thirteen had LVO. The mean NIHSS was 15 (range 0–35) on admission and 18 (0–42) at discharge. Most were cryptogenic (N=7, 46.7%), followed by cardioembolic (N=6, 40%) and large artery-to-artery embolization (N=2, 13.3%). mRS was < 3 in 8 (53%) patients at discharge. None of the patients were on anticoagulation, and five were on antiplatelet therapy pre-hospitalization. Seven received thrombolytics with alteplase (tPA), and 10 had MT.Baseline platelet count was 102 K/uL (range 102–291 K/uL). vWF was measured in 12 patients, all elevated, with seven having levels >400 (180%). ROTEM data was collected in six patients. Three who received tPA had abnormal EXTEM and FIBTEM data (CT extem > 85secs, A10 EXTEM < 45mm, and A10 FIBTEM < 10mm). Notably, INTEM (CT INTEM >208secs) was abnormal in five of the six patients, two of whom did not receive tPA. ConclusionsElevated vWF antigen levels with abnormal ROTEM data suggests that COVID induces changes in the clotting cascade. More robust research is needed to investigate these findings. Thrombolytics, MT, and antiplatelet agents should be utilized to treat COVID-related ischemic stroke based on current clinical guidelines.

Investigations of impact force of the Al–Fe–Cr–Ti alloy by high-velocity compaction

Aluminum alloy materials are the primary choice for lightweight components. High-velocity compaction (HVC) enhances the density of diverse materials. This study utilizes HVC to enhance the density of aluminum alloy. This work examined the influence of compaction velocity, response time (Γ), compaction times, and height-diameter ratio on the impact force of HVC. The maximum force increased linearly with higher compaction velocity, reaching up to 700 kN when the compaction velocity was 9.4 m/s, alongside achieving a peak relative density of 95%. Investigation into the influence of compaction times on the impact force of HVC revealed that the state of powders were critical factors affecting the magnitude of impact force. When the total compaction energy was consistent, the maximum force from double strokes was observed to be lower compared to single stroke. Furthermore, in double strokes with the same second stroke of 55 mm, it was noted that the maximum force increased with higher velocity during the initial compaction. Additionally, both the maximum force and green density decreased as the height-diameter ratio increased. When the height-diameter was 0.4, the maximum force and green density were higher 251 kN, 0.22 g/cm3 than that of 1.2.

Fluctuation theorem in the quantum Otto engine with long-range interaction.

The fluctuation of the quantum Otto engine has recently received a lot of attention, while applying the many body with a long-range interaction to a quantum heat engine may enhance our ability of controlling it. Using the two-point measurement and its generalization, we explore the fluctuation theorem of work and heat in a single stroke as well as in a cycle. We discover that the fluctuations of work in a cycle as well as fluctuations of heat in a single stroke or cycle can be connected to the fluctuation of work in a single stroke. Then we numerically investigate the effect of a long-range interaction on these fluctuation theorems, and our result shows that the fluctuation can be improved by manipulating the long-range interaction.

Research on Bifurcated Origami Hydraulic Dampers for Real Road Vibration Loads

Cylindrical hydraulic dampers are commonly utilized to mitigate vibrations in machinery and structural applications. These devices generally feature a single linear stroke and are often linked to rotary joints to handle complex loading conditions. However, their installation in confined spaces, such as vehicle suspensions, poses considerable difficulties. In this research, we introduce an innovative bifurcated origami hydraulic damper with nonlinear damping capabilities. Initially, we formulated the collapsible conditional equations essential for the design of the bifurcated origami hydraulic dampers. We then examined the fluid dynamics within the damper and its flow channels, determining that the damping force is proportional to the square of the velocity. Furthermore, we developed motion equations based on the derived damping force and suggested vibration analysis methods using the Runge–Kutta approach. For the mass-spring vibration system, we created an experimental setup with the bifurcated origami hydraulic damper and performed vibration tests using noise signals recorded from a vehicle traveling on a gravel road, thus validating its damping performance and efficacy. Additional tests, which varied the orifice size at the end of the origami structure, as well as the type and temperature of the internal fluid, showed that the orifice size had a more pronounced effect on damping efficiency than the fluid type and temperature. This confirmed the vibration-damping effectiveness of the bifurcated origami hydraulic damper.

Reliability assessment of distal occlusion eTICI scoring.

The eThrombolysis in Cerebral Infarction (eTICI) score has been validated in proximal large artery occlusion (pLAOs). Despite the growing number of distal medium vessel occlusions (DMVOs) mechanical thrombectomies (MT) and the widespread utilization of the eTICI scoring system, its reliability and standardization for more distal occlusions have not been validated. We aim to evaluate the interrater reliability of eTICI scores in primary DMVOs. This was a retrospective analysis of a prospectively maintained database for consecutive patients with pLAO and DMVO MT at a single comprehensive stroke center from 2015 to 2022. Two fellowship-trained neurointerventionalists blindly/independently assessed digital subtraction angiograms for final eTICI, followed by consensus reads for discrepancies. 59 DMVO of 2248 thrombectomies [M3:29(50%)/M4:1(2%)/A1:3(5%)/A2:12(22%)/A3: 5(9%)/P1:7(12%)/P2:1(2%)] and 124 pLAOs of 308 thrombectomies [i-ICA:13(11%)/MCA-M1: 111(90%)] were included. The distribution of final eTICI scores was comparable between pLAO vs DMVOs (p = 0.82). The pLAO final eTICI score assessment between two readers demonstrated moderate reliability with a kappa0.77 (95%CI: 0.67-0.88), while the DMVO eTICI score assessment exhibited almost-perfect agreement with kappa 0.94 (95%CI: 0.90-0.99). The agreement between the consensus read and the original report in DMVOs was 0.86 (95% CI: 0.71-1.00) while for pLAO it was 0.83(95% CI: 0.76-0.90). The performance of eTICI was comparable amongst different DMVO territories as well as for distal vs. very distal occlusions. eTICI score exhibited comparable performance for DMVO as compared to pLAO strokes. Further studies investigating DMVO eTICI grading and clinical outcomes are warranted.

Outcome in acute ischemic stroke patients with large-vessel occlusion and initial mild deficits

BackgroundThe management of patients with initially mild acute ischemic stroke (AIS), defined by the National Institutes of Health Stroke Scale (NIHSS) scores 0–5, remains ambiguous despite advances in stroke treatment. The early identification of patients likely to deteriorate is critical in preventing lasting disability.AimsWe investigated the frequency and early predictors of poor functional outcomes in AIS patients with large-vessel occlusion (LVO) and initial mild deficits.MethodsWe performed a retrospective observational study of consecutive AIS patients admitted to a single comprehensive stroke center between 2018 and 2021. The inclusion criteria were a diagnosis of AIS, an arrival NIHSS score of 0–5, imaging-confirmed LVO, and arrival within 24 h of the last-known-well time. The primary outcome was the change in the discharge-modified Rankin Score (ΔmRS) from baseline, categorized as 0–1 (stable outcome) or &amp;gt;1 (poor outcome). Early neurological deterioration was defined as a mean NIHSS score increase of &amp;gt;1 in the first 24-h period. Univariate and multivariable regression analyses were performed. The mean daily NIHSS scores were compared between groups using an analysis of variance (ANOVA).ResultsOf 4,410 stroke admissions, 120 patients met the study inclusion criteria, with 71 (59.2%) patients having a ΔmRS of 0–1 and 49 (40.8%) patients having a ΔmRS of &amp;gt; 1. The mean arrival NIHSS score was similar between groups. However, the mean first-24-h NIHSS score was significantly higher in the poor outcome group vs. the stable outcome group (2.13 vs. 0.95, p &amp;lt; 0.001). A demographic-adjusted multivariable logistic regression revealed that a higher mean first-24-h NIHSS score was the sole early predictor of poor outcome (odds ratio [OR] of 1.65 and a 95% confidence interval [CI] of [1.18, 2.48]). The only association with early neurological deterioration was vertebral artery occlusion, with an OR of 0.35 and a 95% CI of [0.14, 0.81]. The trending mean daily NIHSS scores revealed that patients with poor outcomes deteriorate within 24 h, a significant difference from the stable group (p &amp;lt; 0.001).ConclusionPoor outcomes occurred in a significant proportion of LVO patients with initial mild deficits. The only association was early neurological deterioration. To prevent poor outcomes, rapid identification of any clinical deterioration should prompt consideration of thrombectomy.

Comparison of two automated CT perfusion software packages in patients with ischemic stroke presenting within 24 h of onset.

We compared the ischemic core and hypoperfused tissue volumes estimated by RAPID and JLK-CTP, a newly developed automated computed tomography perfusion (CTP) analysis package. We also assessed agreement between ischemic core volumes by two software packages against early follow-up infarct volumes on diffusion-weighted images (DWI). This retrospective study analyzed 327 patients admitted to a single stroke center in Korea from January 2021 to May 2023, who underwent CTP scans within 24 h of onset. The concordance correlation coefficient (ρ) and Bland-Altman plots were utilized to compare the volumes of ischemic core and hypoperfused tissue volumes between the software packages. Agreement with early (within 3 h from CTP) follow-up infarct volumes on diffusion-weighted imaging (n = 217) was also evaluated. The mean age was 70.7 ± 13.0 and 137 (41.9%) were female. Ischemic core volumes by JLK-CTP and RAPID at the threshold of relative cerebral blood flow (rCBF) < 30% showed excellent agreement (ρ = 0.958 [95% CI, 0.949 to 0.966]). Excellent agreement was also observed for time to a maximum of the residue function (T max) > 6 s between JLK-CTP and RAPID (ρ = 0.835 [95% CI, 0.806 to 0.863]). Although early follow-up infarct volume showed substantial agreement in both packages (JLK-CTP, ρ = 0.751 and RAPID, ρ = 0.632), ischemic core volumes at the threshold of rCBF <30% tended to overestimate ischemic core volumes. JLK-CTP and RAPID demonstrated remarkable concordance in estimating the volumes of the ischemic core and hypoperfused area based on CTP within 24 h from onset.

Exact instanton transseries for quantum mechanics

We calculate the instanton corrections to energy spectra of one-dimensional quantum mechanical oscillators to all orders and unify them in a closed form transseries description. Using alien calculus, we clarify the resurgent structure of these transseries and demonstrate two approaches in which the Stokes constants can be derived. As a result, we formulate a minimal one-parameter transseries for the natural nonperturbative extension to the perturbative energy, which captures the Stokes phenomenon in a single stroke. We derive these results in three models: quantum oscillators with cubic, symmetric double well and cosine potentials. In the latter two examples, we find that the resulting full transseries for the energy has a more convoluted structure that we can factorise in terms of a minimal and a median transseries. For the cosine potential we briefly discuss this more complicated transseries structure in conjunction with topology and the concept of the resurgence triangle.

ASCOD phenotyping of acute vertebrobasilar artery occlusion treated by mechanical thrombectomy: insight from the PERSIST registry.

Determining the underlying etiology of acute vertebrobasilar artery occlusion (VBAO) is crucial for selecting an appropriate treatment approach. The authors aimed to investigate the distribution of etiology and the association with functional outcomes in patients with acute VBAO who underwent endovascular treatment in which atherosclerosis, small-vessel disease, cardiac pathology, other causes, and dissection (ASCOD) phenotyping was used. A retrospective study was conducted at 21 centers in China, involving patients with VBAO who received endovascular treatment within 24 hours of the estimated occlusion time. In the ASCOD phenotyping, each phenotype is graded based on the following categories: 1, likely to be causal; 2, uncertain if causal; and 3, unlikely to be causal. The authors defined a single possible cause as a cause graded 1 in a single domain, and multiple possible causes were graded 1 or 2 regardless of overlap. The primary outcome was unfavorable outcome (modified Rankin Scale [mRS] score of 3-6) at 90 days. The secondary outcomes included shift of mRS score at 90 days, 90-day mortality, successful reperfusion, and National Institutes of Health Stroke Scale score at 24 hours. Multivariable regression analysis was used to assess the association between etiological subtypes and functional outcomes. Multivariate competing-risk regression analysis was performed to analyze the association between etiological subtypes and the risk of recurrent stroke. A total of 577 patients were included in this study. Of these, 521 (90%) had a single possible cause. The most common etiology was A1 (382 cases, 73%), followed by C1 (111 cases, 21%) and O1 (28 cases, 5%-in this study the other causes and dissection subtypes were categorized under the umbrella term of "O" causes). Similar patterns were observed in the multiple possible causes. In the baseline characteristics of the cohort, as rescue therapy, stenting was more frequently used in patients in the A1 group than in the C1 group (53.2% vs 41.7%; p < 0.01). The proportion of atherosclerosis-type etiology increased when the occlusion was located more proximally (p < 0.01). Compared to the A1 group, patients in the C1 group had a lower incidence of unfavorable outcome (OR 0.42, 95% CI 0.24-0.73), which was less likely to shift to a worse mRS score (OR 0.60, 95% CI 0.39-0.91). The O1 subtype was not associated with unfavorable outcome (OR 1.35, 95% CI 0.46-4.01), whereas patients with the O1 subtype were more likely to shift to worse mRS score (OR 2.39, 95% CI 1.09-5.25) and to have a higher 90-day mortality rate (OR 2.60, 95% CI 1.07-6.31). Furthermore, there was no significant association between single etiological subtypes and stroke recurrence within 1 year. The most common etiology in patients with VBAO was atherosclerosis, followed by cardiac pathology and other. Compared to the A1 subgroup, the C1 subgroup showed better functional outcomes, whereas the O1 subgroup showed worse outcomes. Additionally, there was no statistically significant difference in the recurrence risk.

Characteristics of Atherosclerotic Plaques and Stroke Mechanism in Patients with Border-Zone Infarcts: A High-resolution Magnetic Resonance Imaging Study

BackgroundRelatively little is known about the plaque characteristics of border-zone infarcts and how they differ between cortical border-zone (CBZ) and internal border-zone (IBZ) infarcts. MethodsWe conducted a prospective observational cohort study of patients of intracranial atherosclerotic disease who underwent high-resolution magnetic resonance imaging (HR-MRI) examination. Individuals with border-zone infarcts in the middle cerebral artery (MCA) territory, detected by diffusion-weighted imaging, were enrolled. Plaque morphological and compositional parameters of both IBZ and CBZ groups were compared. Independent predictors were identified using a binary logistic regression model, and the sensitivity and specificity of the model were assessed using a receiver operating characteristic curve. Kaplan-Meier survival analysis further explored differences in stroke recurrence between BZ patients with mono or dual antiplatelet therapy. ResultsWe reviewed 101 symptomatic patients with border-zone infarcts (BZ) within the MCA territory in the study. Out of the patients meeting the imaging eligibility criteria, we detected 34 cases with isolated IBZ, 23 cases with isolated CBZ, and 6 cases with both IBZ and CBZ infarcts. Those with IBZ infarcts had a higher plaque burden than those without (p<0.001), and those with CBZ infarcts exhibited a complicated plaque less frequently than those without (37.9% vs 67.6%, p=0.018). In those with isolated IBZ or CBZ infarcts, plaque burden was independently associated with isolated IBZ infarcts (odd ratio=1.08; 95% CI, 1.02-1.15; p=0.023). During the median follow-up period of 37 (27, 50) months, 13.8% of patients receiving early dual antiplatelet treatment and 30.4% of those on single antiplatelet therapy experienced stroke recurrence (p=0.182). ConclusionsIntracranial atherosclerotic plaque morphology and composition differ between patients with IBZ and those with CBZ infarcts. Higher plaque burden is more associated with IBZ infarcts.

Assessing Flash Characteristics in Lightning-Initiated Wildfire Events between 1995 and 2020 within the Contiguous United States

Abstract Twenty-six years of lightning data were paired with over 68 000 lightning-initiated wildfire (LIW) reports to understand lightning flash characteristics responsible for ignition in between 1995 and 2020. Results indicate that 92% of LIW were started by negative cloud-to-ground (CG) lightning flashes and 57% were single stroke flashes. Moreover, 62% of LIW reports did not have a positive CG within 10 km of the start location, contrary to the science literature’s suggestion that positive CG flashes are a dominant fire-starting mechanism. Nearly ⅓ of wildfire events were holdovers, meaning 1 or more days elapsed between lightning occurrence and fire report. However, fires that were reported less than a day after lightning occurrence statistically burned more acreage. Peak current was not found to be a statistically significant delineator between fire starters and non–fire starters for negative CGs but was for positive CGs. Results highlighted the need for reassessing the role of positive CG lightning and subsequently long-continuing current in wildfire ignition started by lightning. One potential outcome of this study’s results is the development of real-time tools to identify ignition potential during lightning events to aid in fire mitigation efforts.