Water striders are impervious to raindrop collision forces and submerged by collapsing craters.

Water striders are abundant in areas with high humidity and rainfall. Raindrops can weigh more than 40 times the adult water strider and some pelagic species spend their entire lives at sea, never contacting ground. Until now, researchers have not systematically investigated the survival of water striders when impacted by raindrops. In this experimental study, we use high-speed videography to film drop impacts on water striders. Drops force the insects subsurface upon direct contact. As the ensuing crater rebounds upward, the water strider is propelled airborne by a Worthington jet, herein called the first jet. We show the water strider's locomotive responses, low density, resistance to wetting when briefly submerged, and ability to regain a super-surface rest state, rendering it impervious to the initial impact. When pulled subsurface during a second crater formation caused by the collapsing first jet, water striders face the possibility of ejection above the surface or submersion below the surface, a fate determined by their position in the second crater. We identify a critical crater collapse acceleration threshold ∼ 5.7 gravities for the collapsing second crater which determines the ejection and submersion of passive water striders. Entrapment by submersion makes the water strider poised to penetrate the air-water interface from below, which appears impossible without the aid of a plastron and proper locomotive techniques. Our study is likely the first to consider second crater dynamics and our results translate to the submersion dynamics of other passively floating particles such as millimetric microplastics atop the world's oceans.

Management of Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis: A Case Report and Literature Review.

INTRODUCTION: Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) is a rare and dangerous dermatologic emergency. It can have different presentations, especially in patients with multiple drug causes, and definitive management of SJS/TEN in these presentations remains unclear. Systemic corticosteroids, TNF inhibitors, and cyclosporine A are promising therapies. CASE REPORT: In this case report, we present a 55-year-old man who developed SJS/TEN while on pembrolizumab and lamotrigine. The patient was treated with corticosteroids and a single dose of etanercept. After a one-week follow-up, the patient’s SJS/TEN had no new activity. DISCUSSION: This literature review highlights how SJS/TEN may present differently in patients on immune checkpoint inhibitors. Treatments in these cases may vary from those with classic SJS/TEN.  Specifically, etanercept given days late into the disease course is effective in speeding re-epithelialization and tapering of already given corticosteroids in classic SJS/TEN. J Drugs Dermatol. 2023;22(11):e24-e28     doi:10.36849/JDD.6999e.

Stabilized detonation for hypersonic propulsion.

Future terrestrial and interplanetary travel will require high-speed flight and reentry in planetary atmospheres by way of robust, controllable means. This, in large part, hinges on having reliable propulsion systems for hypersonic and supersonic flight. Given the availability of fuels as propellants, we likely will rely on some form of chemical or nuclear propulsion, which means using various forms of exothermic reactions and therefore combustion waves. Such waves may be deflagrations, which are subsonic reaction waves, or detonations, which are ultrahigh-speed supersonic reaction waves. Detonations are an extremely efficient, highly energetic mode of reaction generally associated with intense blast explosions and supernovas. Detonation-based propulsion systems are now of considerable interest because of their potential use for greater propulsion power compared to deflagration-based systems. An understanding of the ignition, propagation, and stability of detonation waves is critical to harnessing their propulsive potential and depends on our ability to study them in a laboratory setting. Here we present a unique experimental configuration, a hypersonic high-enthalpy reaction facility that produces a detonation that is fixed in space, which is crucial for controlling and harnessing the reaction power. A standing oblique detonation wave, stabilized on a ramp, is created in a hypersonic flow of hydrogen and air. Flow diagnostics, such as high-speed shadowgraph and chemiluminescence imaging, show detonation initiation and stabilization and are corroborated through comparison to simulations. This breakthrough in experimental analysis allows for a possible pathway to develop and integrate ultra-high-speed detonation technology enabling hypersonic propulsion and advanced power systems.