Unusual chemical compositions of noctilucent-cloud particle nuclei

Two sounding rocket payloads were launched from the ESRO range in Sweden during a noctilucent cloud display. Large numbers of submicron particles were collected, most of which appear to be made up of a high density material coated with a low density material. Typical electron micrographs are shown. Particle chemical compositions have been measured by use of dispersive X-ray analysis equipment attached to an electron microscope and have revealed that most of the high density particle nuclei have atomic weights greater than iron

Cardiovascular Risk, Remote Ischemic Postconditioning, and Endothelial Ischemia-Reperfusion Injury

Remote ischemic postconditioning (rIpost) is a potent vasculoprotective stimulus that is thought to reduce reperfusion injury associated with heart disease. However, certain animal models of cardiometabolic risk factors such as dyslipidemia, diabetes, and hypertension suggest the beneficial effects of rIpost to lessen reperfusion injury may be diminished. These findings have not been studied in clinically relevant humans. The aim of this study was to determine whether the protective effects of rIpost are reduced in the context of raised cardiometabolic risk in humans. Seven participants with raised cardiometabolic risk burden (age:57±7 years; BMI: 31±4kgm2participated in this 2X2 randomized cross-over design study. Raised cardiometabolic risk was established by the presence of 2 or more major risk factors and a 10-year Framingham risk score ≥10%. Microvascular endothelial function was measured using peripheral arterial tonometry (EndoPAT 2000, Itamar Medical Inc.) before and after 20 minutes of left arm, brachial artery ischemia, with and without the induction of rIpost (three, 5-minute bouts of right arm ischemia and reperfusion at 220 mmHg). Remote Ipost procedures were initiated immediately at the onset of reperfusion injury. Microvascular endothelial function was also assessed during a sham trial consisting of mock occlusions at the brachial artery (three, 5-minute inflations at 20 mmHg)