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The results of an experimental investigation of the gaseous cavitation of JP-8 aviation fuel in a converging-diverging nozzle are presented. Fuel cavitation is experimentally characterized by high-speed digital imaging, static pressure distributions, and nonintrusive void fraction and bubble velocity measurements. For comparative purposes, experiments were performed using distilled water and dodecane for the same nozzle and nozzle pressure ratios. Dodecane, the largest component of JP-8 by weight, served as its single-component surrogate. For each working fluid, the experiments examined two different flow regimes: an initially single-phase liquid flow in which no cavitation occurred and another that evolved into two-phase cavitating flow. Additional experiments were performed to study the effect of air bubbles injected into either water or JP-8 at the nozzle inlet. For a sufficiently low range of imposed back pressures, gaseous cavitation led to choked flow for each working fluid. The character of the cavitation in the three fluids was different. These differences are highlighted and plausible mechanisms responsible for the observed behavior are discussed. [ABSTRACT FROM AUTHOR]

The capillary system immediately responds to many pathologies and environmental conditions. Accurate monitoring of its functioning often enables early detection of various diseases related to disorders in skin microcirculation. To expand the scope of capillaroscopy application, it is reasonable to visualize and assess blood microcirculation exactly in the areas of inflamed skin. Body vibrations, breathing, non-flat skin surface and other factors hamper the application of conventional capillaroscopes outside the nailfold area. In this paper, we propose an exoscope-based optical system for high-quality non-invasive computational imaging of capillary network in various areas of the body. Accurate image matching and tracking temporal intensity variations allow detecting the presence of blood pulsations, precise mapping of capillaries and photoplethysmogram acquisition. We have demonstrated the efficiency of the proposed approach experimentally by in vivo mapping and analysis of microvessels in wrist, forearm, upper-arm, breast and hip areas. We believe that the developed system will increase the diagnostic value of video capillaroscopy in clinical practice., Competing Interests: The authors declare no conflicts of interest related to this article., (© 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.)

Introduction: The COVID-19 pandemic dramatically disrupts health care around the globe. The impact of the pandemic on chronic urticaria (CU) and its management are largely unknown., Aim: To understand how CU patients are affected by the COVID-19 pandemic; how specialists alter CU patient management; and the course of CU in patients with COVID-19., Materials and Methods: Our cross-sectional, international, questionnaire-based, multicenter UCARE COVID-CU study assessed the impact of the pandemic on patient consultations, remote treatment, changes in medications, and clinical consequences., Results: The COVID-19 pandemic severely impairs CU patient care, with less than 50% of the weekly numbers of patients treated as compared to before the pandemic. Reduced patient referrals and clinic hours were the major reasons. Almost half of responding UCARE physicians were involved in COVID-19 patient care, which negatively impacted on the care of urticaria patients. The rate of face-to-face consultations decreased by 62%, from 90% to less than half, whereas the rate of remote consultations increased by more than 600%, from one in 10 to more than two thirds. Cyclosporine and systemic corticosteroids, but not antihistamines or omalizumab, are used less during the pandemic. CU does not affect the course of COVID-19, but COVID-19 results in CU exacerbation in one of three patients, with higher rates in patients with severe COVID-19., Conclusions: The COVID-19 pandemic brings major changes and challenges for CU patients and their physicians. The long-term consequences of these changes, especially the increased use of remote consultations, require careful evaluation., (© 2020 The Authors. Allergy published by European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)