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Obtaining accurate temperature measurements with thermocouples in flame environments is challenging due to the effects of radiative heat losses, as these losses are difficult to quantify. Efforts to minimize radiative losses by, for example, suction pyrometry, often result in a significant sacrifice in spatial resolution. In this work, a new experimental methodology is presented that both minimizes the temperature correction and allows the remaining correction to be accurately quantified. The approach is based on increasing and controlling the convective heat transfer to the thermocouple junction, and is accomplished by spinning the thermocouple at high speed. The rotation yields a large and known convective velocity over the thermocouple. Heat transfer can then be modeled for the thermocouple, and a functional relationship between temperature and rotational speed can be found. Fitting this model to the data allows for an accurate temperature correction. To test the feasibility of the rotating thermocouple (RTC) technique for temperature measurement in high temperature gases, experiments were conducted over a range of rotational speeds in a controlled flame where the temperature was known. The measured thermocouple temperatures as a function of rotational speed closely match the theoretical temperatures, yielding a straightforward approach to highly accurate gas temperature measurement. The results also demonstrate limited perturbation to the flow field, even at high rotational speeds. Finally, a method of deconvolution is described that significantly enhances the spatial resolution of the technique, approaching that of a stationary thermocouple. Area (m 2 ) D Diameter of bead (m) ℎ Convective heat transfer coefficient (W/m 2 -K) RTC Rotating thermocouple L Length (m) ܳ ሶ Heat flux (W) r Radius (m) T Temperature (°C) V Velocity (m/s) ω Rotational speed (revolutions/min)

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Background: Atrial Fibrillation (AF) is associated with poorer functional outcomes in acute stroke patients. It has been hypothesized that this is due to poor collateral recruitment. Aims: This study aimed to investigate the relationship between AF and collaterals with outcome in thrombectomy patients. Methods: This retrospective cohort study identified 1036 acute ischemic patients from the INternational Stroke Perfusion Imaging REgistry. The cohort was divided into two groups: 432 with AF and 604 without AF. Patients were stratified by collateral grades as good, moderate, and poor. Within each collateral grade, the prediction of AF vs. No AF for good outcome (3-month modified Rankin Scale of 0-2) was determined. Then, within each collateral grade, perfusion was compared between those with and AF and without AF. Results: AF was negatively associated with good outcome in patients with poor collaterals (26.7% vs. 51.2% for AF vs. No AF, odds ratio=0.32 [95% CI 0.22, 0.50], p<0.001), but not in patients with good (50.9% vs 58.1% for AF vs. No AF, odds ratio=0.75 [0.46, 1.23], p=0.249) or moderate collaterals (43.6% vs 50.9% for AF vs. No AF, odds ratio=0.75 [0.47, 1.18], p=0.214). AF was associated with severe hypoperfusion only in patients with poor collateral flow (54.0 vs. 35.5 ml for AF vs. No AF, p<0.001). Conclusions: AF-related stroke is associated with more severe hypoperfusion and worse outcome in those with poor collaterals.