Global diversity and distribution of antibiotic resistance genes in human wastewater treatment systems
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Science & Technology - Other Topics↗
Engineering topics
Johnson, David
Publications and source records attributed to Johnson, David.
HSV ‐1 ICP0 dimer domain adopts a novel β‐barrel fold
Abstract Infected cell protein 0 (ICP0) is an immediate‐early regulatory protein of herpes simplex virus 1 (HSV‐1) that possesses E3 ubiquitin ligase activity. ICP0 transactivates viral genes, in part, through its C‐terminal dimer domain (residues 555–767). Deletion of this dimer domain results in reduced viral gene expression, lytic infection, and reactivation from latency. Since ICP0's dimer domain is associated with its transactivation activity and efficient viral replication, we wanted to determine the structure of this specific domain. The C‐terminus of ICP0 was purified from bacteria and analyzed by X‐ray crystallography to solve its structure. Each subunit or monomer in the ICP0 dimer is composed of nine β‐strands and two α‐helices. Interestingly, two adjacent β‐strands from one monomer “reach” into the adjacent subunit during dimer formation, generating two β‐barrel‐like structures. Additionally, crystallographic analyses indicate a tetramer structure is formed from two β‐strands of each dimer, creating a “stacking” of the β‐barrels. The structural protein database searches indicate the fold or structure adopted by the ICP0 dimer is novel. The dimer is held together by an extensive network of hydrogen bonds. Computational analyses reveal that ICP0 can either form a dimer or bind to SUMO1 via its C‐terminal SUMO‐interacting motifs but not both. Understanding the structure of the dimer domain will provide insights into the activities of ICP0 and, ultimately, the HSV‐1 life cycle.
Biochemistry & Molecular Biology↗
ORBUMP Pulsed Dipole Magnet Design for Fermilab Booster
Fermilab initiated the accelerator magnet system upgrade project PIP-II for future neutrino experiments. Old ORBUMP pulsed dipoles should be replaced with new stronger magnets occupying the same space as old ones. Four of these magnets connected in series form dogleg type of proton beam orbit. The magnet field and 19 kA current pulse length are close to 1 ms. Old magnet cores were based on a ferrite material. For new magnets, a magnet gap field is above 0.4 T, which completely saturates ferrite material. So, for the magnet core, 0.127 mm thick laminations of low carbon steel with inorganic coating, as the magnet were placed in a vacuum box. There were investigated transient magnet parameters including skin effect in the iron core and in the single-turn copper coil. The integrated field homogeneity was improved by the copper coil shimming. Simulated by OPERA3D power losses were used for the thermal analysis by ANSYS code. The magnet performance is strongly coupled with the power source. The dynamic magnet inductance and resistance were included in the pulsed power source design. Finally, the paper presented the ORBUMP magnet system design.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Status of the laser manipulations of H- beam at J-PARC
The laser manipulations of H- ion beam by single or double neutralization is a very promising technique and highly essential to utilized in accelerator processes such as stripping, pulse chopping, collimation, extraction, and beam diagnostics for the present and future high-intensity proton accelerators. At J-PARC, we are preparing for a POP (Proof-of-Principle) demonstration 400 MeV H- stripping by using only lasers. A prototype YAG laser system and a laser cavity system to reduce the laser power are being developed through 3 MeV H- neutralization studies. Fermilab utilizes H- neutralization at 0.75 MeV by establishing a laser Notcher system for a gap in the H- pulse needed for a clean beam extraction from the ring. To minimize the laser power and maximize the interaction efficiency are common issue at both laboratories. Under the US-Japan collaboration for high-intensity neutrino beam, we are closely working to establish recycling/reusing of seed laser pulses to reduce a size of the laser system. In parallel, we have also developed non-destructive beam diagnostic systems at lower H- energy of 3 MeV, which will be implemented to the 400 MeV as well as easily applicable to the Fermilab linac including PIP-II linac. Installation of the laser system at J-PARC linac for 400 MeV H- stripping is ongoing to start the POP experimental study in 2023.
43 PARTICLE ACCELERATORS↗
Method and system for arbitrary optical pulse generation
A system, method, and apparatus for continuous seed laser pulses supplied to a CW pumped pre-amplifier and/or power-amplifier chain comprises an optical modulator configured to impress pulse signals on an optical signal, a waveform generator configured to establish a structure of the optical signal, and a keep-alive circuit that generates a continuous electrical pulse pattern provided to the optical modulator, wherein the system provides a continuous seed laser pulse structure.
Johnson, David↗
Techno-Economic Assessment for the Production of Hydrocarbon Fuels via Catalytic Upgrading of Furans
This technical report documents the techno-economic analysis (TEA) implications of a biochemical/catalytic pathway for the production of long-chain hydrocarbon fuels in support to the multi-lab Catalytic Upgrading of Biochemical Intermediates (CUBI) project within the Chemical Catalysis for Bioenergy Consortium (ChemCatBio). Two distinct conceptual biorefineries centered around the process encompassing sugar dehydration to furans, aldol condensation between furans and a ketone (methyl ethyl ketone [MEK]), and a final step of hydrotreating to obtain hydrocarbons in the C 14 -C 16 range are considered: an integrated plant that simultaneously produces both furans (furfural and HMF) and ketone (MEK via 2,3-butanediol [BDO]) from sugars and a dedicated facility focused on producing furans from corn stover hydrolysate and procuring the ketone externally. In either plant, the main coproducts are adipic acid (derived from lignin) and sodium sulfate. The results from the assessment are quite comparable to those reported in previous design case focused on biological conversion of sugars to fermentation intermediates with subsequent catalytic upgrading of those intermediates to hydrocarbon fuels, thus presenting another viable alternative pathway to achieve similar fuel cost targets through purely catalytic upgrading of sugars. Since this study considers long-term performance targets for the full pathway dedicated to sugar upgrading to fuels, the critical remaining research points needed to achieve future cost goals are also discussed. Finally, this report presents a single-point sensitivity analysis around selected parameters to identify the major cost drivers of the biorefineries and provides a qualitative discussion on additional opportunities for cost reduction within the proposed concepts, namely through adding value to furans, to coproducts that may be obtained following BDO dehydration, and to lignin through alternative pathways.
09 BIOMASS FUELS↗
An 8 GeV Linac as the Booster Replacement in the Fermilab Power Upgrade
Increasing the Main Injector (MI) beam power above ~1.2 MW requires replacement of the 8 GeV Booster by a higher intensity alternative. Previously, rapid-cycling synchrotron (RCS) and Linac solutions were considered for this purpose. In this paper, we consider the Linac version that produces 8 GeV H⁻ beam for injection into the Recycler Ring (RR) or Main Injector (MI). The Linac takes ~1 GeV beam from the PIP-II Linac and accelerates it to ~2 GeV in a cw SRF linac, followed by a ~2-8 GeV pulsed linac using 1300 MHz cryomodules. The linac components incorporate recent improvements in SRF technology. The linac configuration and beam dynamics requirements are presented. Injection options are discussed. Research needed to implement the Booster replacement is described.
Neuffer, David V.↗
H⁰ Stark Stripping and Component Irradiation in Fermilab Booster
In foil stripping of H⁻ some fraction of the emerging neutral H⁰ will be in excited states, which can then strip through the Stark effect in the magnetic field of the downstream orbit bump magnet. The resultant H⁺ will experience a depleted net kick compared to protons emerging from the foil and will track on trajectories different from the nominal circulating beam. This will lead to irradiation of downstream machine components. An analysis of these processes is of particular importance looking forward to the much higher beam power of the Fermilab PIP-II era. This study investigates where these errant protons will be lost, how much power is deposited, and whether this will be a shielding concern.
43 PARTICLE ACCELERATORS↗
Diflunisal Derivatives as Modulators of ACMS Decarboxylase Targeting the Tryptophan?Kynurenine Pathw
Explore the source record for details and available documents.
Yang, Yu↗
Root traits as drivers of plant and ecosystem functioning: current understanding, pitfalls and future research needs
The effects of plants on the biosphere, atmosphere and geosphere are key determinants of terrestrial ecosystem functioning. However, despite substantial progress made regarding plant belowground components, we are still only beginning to explore the complex relationships between root traits and functions. Drawing on the literature in plant physiology, ecophysiology, ecology, agronomy and soil science, we reviewed 24 aspects of plant and ecosystem functioning and their relationships with a number of root system traits, including aspects of architecture, physiology, morphology, anatomy, chemistry, biomechanics and biotic interactions. Based on this assessment, we critically evaluated the current strengths and gaps in our knowledge, and identify future research challenges in the field of root ecology. Most importantly, we found that belowground traits with the broadest importance in plant and ecosystem functioning are not those most commonly measured. Also, the estimation of trait relative importance for functioning requires us to consider a more comprehensive range of functionally relevant traits from a diverse range of species, across environments and over time series. Finally, we also advocate that establishing causal hierarchical links among root traits will provide a hypothesis-based framework to identify the most parsimonious sets of traits with the strongest links on functions, and to link genotypes to plant and ecosystem functioning.
54 ENVIRONMENTAL SCIENCES↗
Augmenting Space Technology Program Management with Secure Cloud & Mobile Services
The National Aeronautics and Space Administration (NASA) Game Changing Development (GCD) program manages technology projects across all NASA centers and reports to NASA headquarters regularly on progress. Program stakeholders expect an up-to-date, accurate status and often have questions about the program's portfolio that requires a timely response. Historically, reporting, data collection, and analysis were done with manual processes that were inefficient and prone to error. To address these issues, GCD set out to develop a new business automation solution. In doing this, the program wanted to leverage the latest information technology platforms and decided to utilize traditional systems along with new cloud-based web services and gaming technology for a novel and interactive user environment. The team also set out to develop a mobile solution for anytime information access. This paper discusses a solution to these challenging goals and how the GCD team succeeded in developing and deploying such a system. The architecture and approach taken has proven to be effective and robust and can serve as a model for others looking to develop secure interactive mobile business solutions for government or enterprise business automation.
Hodson, Robert F.↗
Space Shuttle 750 psi Helium Regulator Application on Mars Science Laboratory Propulsion
The Mars Science Laboratory (MSL) is NASA's next major mission to Mars, to be launched in September 2009. It is a nuclear powered rover designed for a long duration mission, with an extensive suite of science instruments. The descent and landing uses a unique 'skycrane' concept, where a rocket-powered descent stage decelerates the vehicle, hovers over the ground, lowers the rover to the ground on a bridle, then flies a safe distance away for disposal. This descent stage uses a regulated hydrazine propulsion system. Performance requirements for the pressure regulator were very demanding, with a wide range of flow rates and tight regulated pressure band. These indicated that a piloted regulator would be needed, which are notoriously complex, and time available for development was short. Coincidentally, it was found that the helium regulator used in the Space Shuttle Orbiter main propulsion system came very close to meeting MSL requirements. However, the type was out of production, and fabricating new units would incur long lead times and technical risk. Therefore, the Space Shuttle program graciously furnished three units for use by MSL. Minor modifications were made, and the units were carefully tuned to MSL requirements. Some of the personnel involved had built and tested the original shuttle units. Delta qualification for MSL application was successfully conducted on one of the units. A pyrovalve slam start and shock test was conducted. Dynamic performance analyses for the new application were conducted, using sophisticated tools developed for Shuttle. Because the MSL regulator is a refurbished Shuttle flight regulator, it will be the only part of MSL which has physically already been in space.
Mizukami, Masashi↗
A Model for Dynamic Simulation and Analysis of Tether Momentum Exchange
Momentum-exchange/electrodynamic reboost (MXER) tether systems may enable high-energy missions to the Moon, Mars, and beyond by serving as an 'upper stage in space'. Existing rockets that use an MXER tether station could double their capability to launch communications satellites and help improve US competitiveness. A MXER tether station would boost spacecraft from low Earth orbit to a high-energy orbit quickly, like a high-thrust rocket. Then, using the same principles that make an electric motor work, it would slowly rebuild its orbital momentum by pushing against the Earth's magnetic field-without using any propellant. One of the significant challenges in developing a momentum-exchange/electrodynamic reboost tether systems is in the analysis and design of the capture mechanism and its effects on the overall dynamics of the system. This paper will present a model for a momentum-exchange tether system that can simulate and evaluate the performance and requirements of such a system.
Canfield, Stephen↗
JTEC panel report on machine translation in Japan
The goal of this report is to provide an overview of the state of the art of machine translation (MT) in Japan and to provide a comparison between Japanese and Western technology in this area. The term 'machine translation' as used here, includes both the science and technology required for automating the translation of text from one human language to another. Machine translation is viewed in Japan as an important strategic technology that is expected to play a key role in Japan's increasing participation in the world economy. MT is seen in Japan as important both for assimilating information into Japanese as well as for disseminating Japanese information throughout the world. Most of the MT systems now available in Japan are transfer-based systems. The majority of them exploit a case-frame representation of the source text as the basis of the transfer process. There is a gradual movement toward the use of deeper semantic representations, and some groups are beginning to look at interlingua-based systems.
Carbonell, Jaime↗