2,041 research outputs found

    Hoogsteen base pairs proximal and distal to echinomycin binding sites on DNA

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    Forms of the DNA double helix containing non-Watson-Crick base-pairing have been discovered recently based on x-ray diffraction analysis of quinoxaline antibiotic-oligonucleotide complexes. In an effort to find evidence for Hoogsteen base-pairing at quinoxaline-binding sites in solution, chemical "footprinting" (differential cleavage reactivity) of echinomycin bound to DNA restriction fragments was examined. We report that purines (A>G) in the first and/or fourth base-pair positions of occupied echinomycin-binding sites are hyperreactive to diethyl pyrocarbonate. The correspondence of the solid-state data and the sites of diethyl pyrocarbonate hyperreactivity suggests that diethyl pyrocarbonate may be a sensitive reagent for the detection of Hoogsteen base-pairing in solution. Moreover, a 12-base-pair segment of alternating A-T DNA, which is 6 base pairs away from the nearest strong echinomycin-binding site, is also hyperreactive to diethyl pyrocarbonate in the presence of echinomycin. This hyperreactive segment may be an altered form of right-handed DNA that is entirely Hoogsteen base-paired

    COVID-19 Pandemic and Radiology: Facts, Resources, and Suggestions for Near-term Protocols

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    The purpose of this editorial is to offer a synopsis about the COVID-19 pandemic and to present some recommendations as they relate to the practice of radiology, focused on Low- and Middle-Income Countries (LMIC). Health departments and professional bodies around the world are issuing guidelines for personal protection and patient handling in radiology. In High-Income Countries (HIC) these guidelines have been periodically updated as knowledge evolves about COVID-19 viral disease (1,2,3). The HIC guidelines assume the availability of portable radiography, ability to reserve one of many CT scanners only for COVID-19 patients, supply of a whole range of personal protective equipment (PPE), sanitizers and a variety of disinfecting chemicals. Nevertheless the exponential spread of COVID-19 is causing shortages of supplies in regions with supposedly “unlimited” resources. Much continues to be published on the rapidly evolving body of knowledge on this highly contagious respiratory infection, with a much higher mortality compared to the Influenza-A virus responsible for respiratory disease during “flu season” (4). Concurrently, speculative and false information is being exchanged on social media by “experts” from all walks of life offering “science” on the current pandemic. We urge our readers to use resources from established health organizations and universities, many of whom are referenced in this editorial

    The Nature of Enzyme Action.

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    The Operational-Bayesian Approach In Reliability Theory

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    nuloWe emphasize the derivation of likelihood models starting from a well specified problem of interest and finite populations. "Parameters" are given operational meaning. In particular, parameters are specified in terms of different forms of energy. Examples relevant to reliability theory are used to illustrate ideas. Examples in engineering probability are given

    PACS for the Developing World

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    Digital imaging is now firmly ensconced in the developed world. Its widespread adoption has enabled instant access to images, remote viewing, remote consultation, and the end of lost or misplaced film. Unfortunately, the current paradigm of Picture Archiving and Communication System (PACS), with advanced technology inseparable from high complexity, high purchase costs, and high maintenance costs, is not suited for the low-income developing world. Like the simple, easy to repair, 1950’s American cars still running on the streets of Havana, the developing world requires a PACS (DW-PACS) that can perform basic functions and survive in a limited-resource environment. The purpose of this article is to more fully describe this concept and to present a blueprint for PACS tailored to the needs and resources of the developing world. This framework should assist both users looking for a vendor-supplied or open-source solutions and developers seeking to address the needs of this emerging market

    Vanishing of Gravitational Particle Production in the Formation of Cosmic Strings

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    We consider the gravitationally induced particle production from the quantum vacuum which is defined by a free, massless and minimally coupled scalar field during the formation of a gauge cosmic string. Previous discussions of this topic estimate the power output per unit length along the string to be of the order of 106810^{68} ergs/sec/cm in the s-channel. We find that this production may be completely suppressed. A similar result is also expected to hold for the number of produced photons.Comment: 10 pages, Plain LaTex. Minor improvements. To appear in PR

    Report to the Aerozone Alliance: Phase 1

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    The origins for this project include a 2011 Cleveland State University feasibility report which provided research on “aerotropolis” developments in general and describes planned development outward from an airport with observations specifically for Cleveland. Subsequently or concurrently, Cuyahoga County Council introduced a resolution to support early efforts to collaborate with stakeholders for the purpose of promoting economic development, job creation, job retention, and workforce development around Cleveland Hopkins airport. The Aerozone Alliance has been organized to create the conditions for an airport city or “aerotropolis” to take shape. The Aerozone Alliance region comprises more than 7,000 land parcels around Cleveland Hopkins airport in multiple political jurisdictions that offer potential to be developed into an “aerotropolis. This project involved technical assistance performed by the Center for Nonprofit Policy & Practice to assist in organizing the effort. This report draws on a scope of work intended to: assist in developing the design and composition of the Aerozone Alliance board membership, governance, working committee structure, and work project implementation; set the conditions for a mutually agreeable work plan for the board and its committees with project outcomes; and provide support in the form of staffing to organize stakeholders which may include: 1) preparing four meeting agendas; 2) note-taking at meetings with written minutes; 3) coordinating communications of the committee members; and 4) research as required

    Current Concepts Imaging in COVID-19 and the Challenges for Low and Middle Income Countries

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    With nearly 3,800,000 cases and 270,000 deaths reported worldwide, COVID-19 is a global pandemic unlike any we have seen in our lifetimes (1). As early as 1995, the WHO was warning of a global infectious disease crisis, citing 30 new infectious diseases emerging in the past 20 years, loss of antibiotic effectiveness, low rates of immunization, poverty, and inadequate investment in public health contributing to the more than 17 million people dying each year from infectious diseases, principally in Low and Middle Income countries (LMIC) (2). Unlike previous infectious diseases, at the time of this writing over 63% of the total reported cases of COVID-19 are in 6 High Income Countries (HIC): USA, Italy, Spain, France, Germany and the UK. Information concerning the imaging findings in COVID-19 has been rapidly disseminated from the centers first affected by the pandemic. This article attempts to summarize the current state of knowledge regarding the imaging findings in COVID-19, focusing on pulmonary findings, and offer recommendation for the use of imaging for diagnosis and surveillance of COVID-19, particularly in LMIC
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