Case Western Reserve University

About: Case Western Reserve University is a education organization based out in Cleveland, Ohio, United States. It is known for research contribution in the topics: Population & Health care. The organization has 54617 authors who have published 106568 publications receiving 5071613 citations. The organization is also known as: Case & Case Western.

From unwinding to clamping — the DEAD box RNA helicase family

Abstract: RNA helicases of the DEAD box family are present in all eukaryotic cells and in many bacteria and Archaea. These highly conserved enzymes are required for RNA metabolism from transcription to degradation and are therefore important players in gene expression. DEAD box proteins use ATP to unwind short duplex RNA in an unusual fashion and remodel RNA-protein complexes, but they can also function as ATP-dependent RNA clamps to provide nucleation centres that establish larger RNA-protein complexes. Structural, mechanistic and molecular biological studies have started to reveal how these conserved proteins can perform such diverse functions and how accessory proteins have a central role in their regulation.

Catalysts for nitrogen reduction to ammonia

Abstract: The production of synthetic ammonia remains dependent on the energy- and capital-intensive Haber–Bosch process. Extensive research in molecular catalysis has demonstrated ammonia production from dinitrogen, albeit at low production rates. Mechanistic understanding of dinitrogen reduction to ammonia continues to be delineated through study of molecular catalyst structure, as well as through understanding the naturally occurring nitrogenase enzyme. The transition to Haber–Bosch alternatives through robust, heterogeneous catalyst surfaces remains an unsolved research challenge. Catalysts for electrochemical reduction of dinitrogen to ammonia are a specific focus of research, due to the potential to compete with the Haber–Bosch process and reduce associated carbon dioxide emissions. However, limited progress has been made to date, as most electrocatalyst surfaces lack specificity towards nitrogen fixation. In this Review, we discuss the progress of the field in developing a mechanistic understanding of nitrogenase-promoted and molecular catalyst-promoted ammonia synthesis and provide a review of the state of the art and scientific needs for heterogeneous electrocatalysts. The artificial synthesis of ammonia remains one of the most important catalytic processes worldwide, over 100 years after its development. In this Review, recent developments in enzymatic, homogeneous and heterogeneous catalysis towards the conversion of nitrogen to ammonia are discussed, with a particular focus on how mechanistic understanding informs catalyst design.

Bank Liquidity Creation

Abstract: Although the modern theory of financial intermediation portrays liquidity creation as an essential role of banks, comprehensive measures of bank liquidity creation do not exist. We construct four measures and apply them to data on virtually all U.S. banks from 1993 to 2003. We find that bank liquidity creation increased every year and exceeded $2.8 trillion in 2003. Large banks, multibank holding company members, retail banks, and recently merged banks created the most liquidity. Bank liquidity creation is positively correlated with bank value. Testing recent theories of the relationship between capital and liquidity creation, we find that the relationship is positive for large banks and negative for small banks. (JEL G21, G28, G32)

Stimuli-Responsive Polymer Nanocomposites Inspired by the Sea Cucumber Dermis

Abstract: Sea cucumbers, like other echinoderms, have the ability to rapidly and reversibly alter the stiffness of their inner dermis. It has been proposed that the modulus of this tissue is controlled by regulating the interactions among collagen fibrils, which reinforce a low-modulus matrix. We report on a family of polymer nanocomposites, which mimic this architecture and display similar chemoresponsive mechanic adaptability. Materials based on a rubbery host polymer and rigid cellulose nanofibers exhibit a reversible reduction by a factor of 40 of the tensile modulus, for example, from 800 to 20 megapascals (MPa), upon exposure to a chemical regulator that mediates nanofiber interactions. Using a host polymer with a thermal transition in the regime of interest, we demonstrated even larger modulus changes (4200 to 1.6 MPa) upon exposure to emulated physiological conditions.

Spectroscopic Discovery of the Supernova 2003dh Associated with GRB 030329

Abstract: We present early observations of the afterglow of the Gamma-Ray Burst (GRB) 030329 and the spectroscopic discovery of its associated supernova SN 2003dh. We obtained spectra of the afterglow of GRB 030329 each night from March 30.12 (0.6 days after the burst) to April 8.13 (UT) (9.6 days after the burst). The spectra cover a wavelength range of 350 nm to 850 nm. The early spectra consist of a power-law continuum (F_nu ~ nu^{-0.9}) with narrow emission lines originating from HII regions in the host galaxy, indicating a low redshift of z=0.1687. However, our spectra taken after 2003 Apr. 5 show broad peaks in flux characteristic of a supernova. Correcting for the afterglow emission, we find the spectrum of the supernova is remarkably similar to the type Ic `hypernova' SN 1998bw. While the presence of supernovae have been inferred from the light curves and colors of GRB afterglows in the past, this is the first direct, spectroscopic confirmation that a subset of classical gamma-ray bursts originate from supernovae.