Quantization of Midisuperspace Models

We give a comprehensive review of the quantization of midisuperspace models. Though the main focus of the paper is on quantum aspects, we also provide an introduction to several classical points related to the definition of these models. We cover some important issues, in particular, the use of the principle of symmetric criticality as a very useful tool to obtain the required Hamiltonian formulations. Two main types of reductions are discussed: those involving metrics with two Killing vector fields and spherically symmetric models. We also review the more general models obtained by coupling matter fields to these systems. Throughout the paper we give separate discussions for standard quantizations using geometrodynamical variables and those relying on loop quantum gravity inspired methods.Comment: To appear in Living Review in Relativit

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Endothelial Glycocalyx and Cardiomyocyte Damage Is Prevented by Recombinant Syndecan-1 in Acute Myocardial Infarction

The outer layer of endothelial cells (ECs), consisting of the endothelial glycocalyx (eGC) and the cortex (CTX), provides a protective barrier against vascular diseases. Structural and functional impairments of their mechanical properties are recognized as hallmarks of endothelial dysfunction and can lead to cardiovascular events, such as acute myocardial infarction (AMI). This study investigated the effects of AMI on endothelial nanomechanics and function and the use of exogenous recombinant syndecan-1 (rSyn-1), a major component of the eGC, as recovering agent. ECs were exposed in vitro to serum samples collected from patients with AMI. In addition, in situ ECs of ex vivo aorta preparations derived from a mouse model for AMI were employed. Effects were quantified by using atomic force microscopy-based nanoindentation measurements, fluorescence staining, and histologic examination of the mouse hearts. AMI serum samples damaged eGC/CTX and augmented monocyte adhesion to the endothelial surface. In particular, the anaphylatoxins C3a and C5a played an important role in these processes. The impairment of endothelial function could be prevented by rSyn-1 treatment. In the mouse model of myocardial infarction, pretreatment with rSyn-1 alleviated eGC/CTX deterioration and reduced cardiomyocyte damage in histologic analyses. However, echocardiographic measurements did not indicate a functional benefit. These results provide new insights into the underlying mechanisms of AMI-induced endothelial dysfunction and perspectives for future studies on the benefit of rSyn-1 in post-AMI treatment