Individual Nanostructures in an Epsilon-Near-Zero Material Probed with 3D-Sculpted Light

Epsilon-near-zero (ENZ) materials, i.e., materials with vanishing real part of the permittivity, have become an increasingly desirable platform for exploring linear and nonlinear optical phenomena in nanophotonic and on-chip environments. ENZ materials inherently enhance electric fields for properly chosen interaction scenarios, host extreme nonlinear optical effects, and lead to other intriguing phenomena. To date, studies in the optical domain mainly focused on nanoscopically thin films of ENZ materials and their interaction with light and other nanostructured materials. Here, the optical response of individual nanostructures milled into an ENZ material are explored both experimentally and numerically. For the study, 3D structured light beams are employed, allowing for the full utilization of polarization-dependent field enhancements enabled by a tailored illumination and a vanishing permittivity. This study reveals the underlying intricate interaction mechanisms and showcase the polarization-dependent controllability, paving the way towards experiments in the nonlinear optical regime where the presented effects will enable polarization-controlled nonlinear refractive index based ultra-fast switching on the single nanostructure level.Comment: 7 pages, 8 figure

A Large U3 Deletion Causes Increased In Vivo Expression From a Nonintegrating Lentiviral Vector

The feasibility of employing nonintegrating lentiviral vectors has been demonstrated by recent studies showing the ability of nonintegrating lentiviral vectors to maintain transgene expression in vitro and in vivo. Furthermore, HIV-1 vectors packaged with a mutated integrase were able to correct retinal disease in a mouse model. Interestingly, these results differ from earlier studies in which first-generation nonintegrating lentiviral vectors yielded insignificant levels of transduction. However, to date a rigorous characterization of transgene expression from the currently used self-inactivating (SIN) nonintegrating lentiviral vectors has not been published. Here we characterize transgene expression from SIN nonintegrating lentiviral vectors. Overall, we found that nonintegrating vectors express transgenes at a significantly lower level than their integrating counterparts. Expression from nonintegrating vectors was improved upon introducing a longer deletion in the vector’s U3 region. A unique shuttle-vector assay indicated that the relative abundance of the different episomal forms was not altered by the longer U3 deletion. Interestingly, the longer U3 deletion did not enhance expression in the corpus callosum of the rat brain, suggesting that the extent of silencing of episomal transcription is influenced by tissue-specific factors. Finally, and for the first time, episomal expression in the mouse liver was potent and sustained

Hydrogen-Based Metabolism as an Ancestral Trait in Lineages Sibling to the Cyanobacteria

© 2019, The Author(s). The evolution of aerobic respiration was likely linked to the origins of oxygenic Cyanobacteria. Close phylogenetic neighbors to Cyanobacteria, such as Margulisbacteria (RBX-1 and ZB3), Saganbacteria (WOR-1), Melainabacteria and Sericytochromatia, may constrain the metabolic platform in which aerobic respiration arose. Here, we analyze genomic sequences and predict that sediment-associated Margulisbacteria have a fermentation-based metabolism featuring a variety of hydrogenases, a streamlined nitrogenase, and electron bifurcating complexes involved in cycling of reducing equivalents. The genomes of ocean-associated Margulisbacteria encode an electron transport chain that may support aerobic growth. Some Saganbacteria genomes encode various hydrogenases, and others may be able to use O2 under certain conditions via a putative novel type of heme copper O2 reductase. Similarly, Melainabacteria have diverse energy metabolisms and are capable of fermentation and aerobic or anaerobic respiration. The ancestor of all these groups may have been an anaerobe in which fermentation and H2 metabolism were central metabolic features. The ability to use O2 as a terminal electron acceptor must have been subsequently acquired by these lineages

Standardizing data reporting in the research community to enhance the utility of open data for SARS-CoV-2 wastewater surveillance

SARS-CoV-2 RNA detection in wastewater is being rapidly developed and adopted as a public health monitoring tool worldwide. With wastewater surveillance programs being implemented across many different scales and by many different stakeholders, it is critical that data collected and shared are accompanied by an appropriate minimal amount of meta-information to enable meaningful interpretation and use of this new information source and intercomparison across datasets. While some databases are being developed for specific surveillance programs locally, regionally, nationally, and internationally, common globally-adopted data standards have not yet been established within the research community. Establishing such standards will require national and international consensus on what meta-information should accompany SARS-CoV-2 wastewater measurements. To establish a recommendation on minimum information to accompany reporting of SARS-CoV-2 occurrence in wastewater for the research community, the United States National Science Foundation (NSF) Research Coordination Network on Wastewater Surveillance for SARS-CoV-2 hosted a workshop in February 2021 with participants from academia, government agencies, private companies, wastewater utilities, public health laboratories, and research institutes. This report presents the primary two outcomes of the workshop: (i) a recommendation on the set of minimum meta-information that is needed to confidently interpret wastewater SARS-CoV-2 data, and (ii) insights from workshop discussions on how to improve standardization of data reporting

LSST Science Book, Version 2.0

A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable objects both at low and high redshift, and the properties of normal and active galaxies at low and high redshift. It then turns to far-field cosmological topics, exploring properties of supernovae to z~1, strong and weak lensing, the large-scale distribution of galaxies and baryon oscillations, and how these different probes may be combined to constrain cosmological models and the physics of dark energy.Comment: 596 pages. Also available at full resolution at http://www.lsst.org/lsst/sciboo

LSST: from Science Drivers to Reference Design and Anticipated Data Products

(Abridged) We describe here the most ambitious survey currently planned in the optical, the Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. LSST will be a wide-field ground-based system sited at Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg$^2$ field of view, and a 3.2 Gigapixel camera. The standard observing sequence will consist of pairs of 15-second exposures in a given field, with two such visits in each pointing in a given night. With these repeats, the LSST system is capable of imaging about 10,000 square degrees of sky in a single filter in three nights. The typical 5$\sigma$ point-source depth in a single visit in $r$ will be $\sim 24.5$ (AB). The project is in the construction phase and will begin regular survey operations by 2022. The survey area will be contained within 30,000 deg$^2$ with $\delta<+34.5^\circ$, and will be imaged multiple times in six bands, $ugrizy$, covering the wavelength range 320--1050 nm. About 90\% of the observing time will be devoted to a deep-wide-fast survey mode which will uniformly observe a 18,000 deg$^2$ region about 800 times (summed over all six bands) during the anticipated 10 years of operations, and yield a coadded map to $r\sim27.5$. The remaining 10\% of the observing time will be allocated to projects such as a Very Deep and Fast time domain survey. The goal is to make LSST data products, including a relational database of about 32 trillion observations of 40 billion objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures available from https://www.lsst.org/overvie

Recommendations on data sharing in HIV drug resistance research

• Human immunodeficiency virus (HIV) drug resistance has implications for antiretroviral treatment strategies and for containing the HIV pandemic because the development of HIV drug resistance leads to the requirement for antiretroviral drugs that may be less effective, less well-tolerated, and more expensive than those used in first-line regimens.  • HIV drug resistance studies are designed to determine which HIV mutations are selected by antiretroviral drugs and, in turn, how these mutations affect antiretroviral drug susceptibility and response to future antiretroviral treatment regimens.  • Such studies collectively form a vital knowledge base essential for monitoring global HIV drug resistance trends, interpreting HIV genotypic tests, and updating HIV treatment guidelines.  • Although HIV drug resistance data are collected in many studies, such data are often not publicly shared, prompting the need to recommend best practices to encourage and standardize HIV drug resistance data sharing.  • In contrast to other viruses, sharing HIV sequences from phylogenetic studies of transmission dynamics requires additional precautions as HIV transmission is criminalized in many countries and regions.  • Our recommendations are designed to ensure that the data that contribute to HIV drug resistance knowledge will be available without undue hardship to those publishing HIV drug resistance studies and without risk to people living with HIV