54 research outputs found
New In Situ-Generated Polymer-Iodine Complexes with Broad-Spectrum Antimicrobial Activity
Iodine-containing systems show broad antiseptic properties that can be an invaluable tool in controlling infections in humans and animals. Here, we describe the first proof-of-concept studies on biocidal active polyamide- and polyurethane-iodine complexes that are produced in situ directly during the fabrication and/or polymerization process at laboratory and commercially relevant scales. These polymer-iodine materials are active against a broad range of microorganisms, including bacteria and fungi. It is suggested that the ease of manufacture and subsequent commercialization make said systems especially suited for applications as base materials for medical devices to reduce infection risks and control the spread of pathogens. IMPORTANCE Infectious diseases are of mounting medical and public concern. A major contributor to this trend is the proliferation of medical implants, which are inherently vulnerable to microbial contamination and the subsequent onset of hospital-acquired infections. Moreover, implant-associated infections in humans are often difficult to diagnose and treat and are associated with substantial health care costs. Here, we present the development of biocidal active polyamide- and polyurethane-iodine complexes that are generated in situ during fabrication. We show that the excellent antiseptic properties of water-soluble povidone-iodine can be similarly realized in water-insoluble engineering plastics, specifically polyamide- and polyurethane-iodine. These complexes have inherent biocidal activity against major pathogenic bacteria and fungi
Multicone Diamond Waveguides for Nanoscale Quantum Sensing
The long-lived electronic spin of the nitrogen-vacancy (NV) center in diamond
is a promising quantum sensor for detecting nanoscopic magnetic and electric
fields in a variety of experimental conditions. Nevertheless, an outstanding
challenge in improving measurement sensitivity is the poor signal-to-noise
ratio (SNR) of prevalent optical spin-readout techniques. Here, we address this
limitation by coupling individual NV centers to optimized diamond nanopillar
structures, thereby improving optical collection efficiency of fluorescence.
First, we optimize the structure in simulation, observing an increase in
collection efficiency for tall ( 5 m) pillars with tapered
sidewalls. We subsequently verify these predictions by fabricating and
characterizing a representative set of structures using a reliable and
reproducible nanofabrication process. An optimized device yields increased SNR,
owing to improvements in collimation and directionality of emission.
Promisingly, these devices are compatible with low-numerical-aperture,
long-working-distance collection optics, as well as reduced tip radius,
facilitating improved spatial resolution for scanning applications.Comment: 22 pages, five figure
Snowmass 2021 Topical Report on Synergies in Research at Underground Facilities
This is a Snowmass 2021 Topical Report for the Underground Facilities and
Infrastructure Frontier on Synergies in Research at Underground Facilities: A
broad range of scientific and engineering research is possible in underground
laboratories, beyond the physics-focused activities described in the other
Underground Facilities and Infrastructure Topical Reports. These areas of
research include nuclear astrophysics, geology, geoengineering, gravitational
wave detection, biology, and perhaps soon quantum information science. This UF
Topical Report will survey those other scientific and engineering research
activities that share interest in research-orientated Underground Facilities
and Infrastructure. In most cases the breadth and depth of research aims is too
large to cover in completeness and references to surveys or key documents for
those fields are provided after introductory summaries. Additional attention is
then given to shared, similar, and unique needs of each research area with
respect to the broader underground research community's Underground Facilities
and Infrastructure needs. Where potential conflicts of usage type, site, or
duration might arise, these are identified.Comment: Snowmass 2021 Topical Report (UF5
Aquilegia, Vol. 37 No. 5, Fall 2013, Newsletter of the Colorado Native Plant Society
https://epublications.regis.edu/aquilegia/1145/thumbnail.jp
Major flaws in conflict prevention policies towards Africa : the conceptual deficits of international actorsâ approaches and how to overcome them
Current thinking on African conflicts suffers from misinterpretations oversimplification, lack of focus, lack of conceptual clarity, state-centrism and lack of vision). The paper analyses a variety of the dominant explanations of major international actors and donors, showing how these frequently do not distinguish with sufficient clarity between the âroot causesâ of a conflict, its aggravating factors and its triggers. Specifically, a correct assessment of conflict prolonging (or sustaining) factors is of vital importance in Africaâs lingering confrontations. Broader approaches (e.g. âstructural stabilityâ) offer a better analytical framework than familiar one-dimensional explanations. Moreover, for explaining and dealing with violent conflicts a shift of attention from the nation-state towards the local and sub-regional level is needed.Aktuelle Analysen afrikanischer Gewaltkonflikte sind hĂ€ufig voller Fehlinterpretationen (Mangel an Differenzierung, Genauigkeit und konzeptioneller Klarheit, Staatszentriertheit, fehlende mittelfristige Zielvorstellungen). Breitere AnsĂ€tze (z. B. das Modell der Strukturellen StabilitĂ€t) könnten die Grundlage fĂŒr bessere Analyseraster und Politiken sein als eindimensionale ErklĂ€rungen. hĂ€ufig differenzieren ErklĂ€rungsansĂ€tze nicht mit ausreichender Klarheit zwischen Ursachen, verschĂ€rfenden und auslösenden Faktoren. Insbesondere die richtige Einordnung konfliktverlĂ€ngernder Faktoren ist in den jahrzehntelangen gewaltsamen Auseinandersetzungen in Afrika von zentraler Bedeutung. Das Diskussionspapier stellt die groĂe Variationsbreite dominanter ErklĂ€rungsmuster der wichtigsten internationalen Geber und Akteure gegenĂŒber und fordert einen Perspektivenwechsel zum Einbezug der lokalen und der subregionalen Ebene fĂŒr die ErklĂ€rung und Bearbeitung gewaltsamer Konflikte
The October 2012 magnitude (Mw) 7.8 earthquake offshore Haida Gwaii, Canada
Alison L. Bird et al. report on the Mw 7.8 earthquake offshore Haida Gwaii, Canada, from 2012 for the Summary of the Bulletin of the International Seismological Centre
Silencing and Un-silencing of Tetracycline-Controlled Genes in Neurons
To identify the underlying reason for the controversial performance of tetracycline (Tet)-controlled regulated gene expression in mammalian neurons, we investigated each of the three components that comprise the Tet inducible systems, namely tetracyclines as inducers, tetracycline-transactivator (tTA) and reverse tTA (rtTA), and tTA-responsive promoters (Ptets). We have discovered that stably integrated Ptet becomes functionally silenced in the majority of neurons when it is inactive during development. Ptet silencing can be avoided when it is either not integrated in the genome or stably-integrated with basal activity. Moreover, long-term, high transactivator levels in neurons can often overcome integration-induced Ptet gene silencing, possibly by inducing promoter accessibility
Taxation and Democratization
Anecdotal evidence from pre-modern Europe and North America suggests that rulers are forced to become more democratic once they impose a significant fiscal burden on their citizens. One difficulty in testing this taxation causes democratization hypothesis empirically is the endogeneity of public revenues. I use introductions of value added taxes and autonomous revenue authorities as sources of quasi-exogenous variation to identify the causal effect of the fiscal burden borne by citizens on democracy. The instrumental variables regressions with a panel of 122 countries over the period 1981-2008 suggest that revenues had on average a mild positive effect on democracy
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