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At least 1,747 records · Page 97

Impact of primer dimers and self-amplifying hairpins on reverse transcription loop-mediated isothermal amplification detection of viral RNA

Loop-mediated isothermal amplification (LAMP), coupled with reverse transcription (RT), has become a popular technique for detection of viral RNA due to several desirable characteristics for use in point-of-care or low-resource settings. The large number of primers in LAMP (six per target) leads to an increased likelihood of primer-dimer interactions, and the inner primers in particular are prone to formation of stable hairpin structures due to their length (typically 40-45 bases). Although primer-dimers and hairpin structures are known features to avoid in nucleic acid amplification techniques, there is little quantitative information in literature regarding the impact of these structures on LAMP or RT-LAMP assays. In this study, we examine the impact of primer-dimers and hairpins on previously-published primer sets for dengue virus and yellow fever virus. We demonstrate that minor changes to the primers to eliminate amplifiable primer dimers and hairpins improves the performance of the assays when monitored in real time with intercalating dyes, and when monitoring a fluorescent endpoint using the QUASR technique. We also discuss the thermodynamic implications of these minor changes on the overall stability of amplifiable secondary structures, and we present a single thermodynamic parameter to predict the probability of non-specific amplification associated with LAMP primers.

59 BASIC BIOLOGICAL SCIENCES↗

Probing C–I bond fission in the UV photochemistry of 2-iodothiophene with core-to-valence transient absorption spectroscopy

The UV photochemistry of small heteroaromatic molecules serves as a testbed for understanding fundamental photo-induced chemical transformations in moderately complex compounds, including isomerization, ring-opening, and molecular dissociation. Here, a combined experimental-theoretical study of 268 nm UV light-induced dynamics in 2-iodothiophene (C 4 H 3 IS) is performed. The dynamics are experimentally monitored with a femtosecond extreme ultraviolet (XUV) probe that measures iodine N-edge 4d core-to-valence transitions. Experiments are complemented by density functional theory calculations of both the pump-pulse induced valence excitations and the XUV probe-induced core-to-valence transitions. Possible intramolecular relaxation dynamics are investigated by ab initio molecular dynamics simulations. Furthermore, gradual absorption changes up to ~0.5 to 1 ps after excitation are observed for both the parent molecular species and emerging iodine fragments, with the latter appearing with a characteristic rise time of 160 ± 30 fs. Comparison of spectral intensities and energies with the calculations identifies an iodine dissociation pathway initiated by a predominant π → π* excitation. In contrast, initial excitation to a nearby n ⟂ → σ* state appears unlikely based on a significantly smaller oscillator strength and the absence of any corresponding XUV absorption signatures. Excitation to the π → π* state is followed by contraction of the C–I bond, enabling a nonadiabatic transition to a dissociative π→σ C-I * state. For the subsequent fragmentation, a relatively narrow bond-length region along the C–I stretch coordinate between 230 and 280 pm is identified, where the transition between the parent molecule and the thienyl radical + iodine atom products becomes prominent in the XUV spectrum due to rapid localization of two singly occupied molecular orbitals on the two fragments.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

A review of the use and potential of the GATE Monte Carlo simulation code for radiation therapy and dosimetry applications

In this paper, the authors' review the applicability of the open-source GATE Monte Carlo simulation platform based on the GEANT4 toolkit for radiation therapy and dosimetry applications. The many applications of GATE for state-of-the-art radiotherapy simulations are described including external beam radiotherapy, brachytherapy, intraoperative radiotherapy, hadrontherapy, molecular radiotherapy, and in vivo dose monitoring. Investigations that have been performed using GEANT4 only are also mentioned to illustrate the potential of GATE. The very practical feature of GATE making it easy to model both a treatment and an imaging acquisition within the same frameworkis emphasized. The computational times associated with several applications are provided to illustrate the practical feasibility of the simulations using current computing facilities.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

SU-E-T-139: Automated Daily EPID Exit Dose Analysis Uncovers Treatment Variations

Purpose: To evaluate a fully automated EPID exit dose system for its ability to detect daily treatment deviations including patient setup, delivery, and anatomy changes. Methods: PerFRACTION (Sun Nuclear Corporation) software is a system that uses integrated EPID images taken during patient treatment and automatically pulled from the Aria database and analyzed based on user-defined comparisons. This was used to monitor 20 plans consisting of a total of 859 fields for 18 patients, for a total of 251 fractions. Nine VMAT, 5 IMRT, and 6 3D plans were monitored. The Gamma analysis was performed for each field within a plan, comparing the first fraction against each of the other fractions in each treatment course. A 2% dose difference, 1 mm distance-to-agreement, and 10% dose threshold was used. These tight tolerances were chosen to achieve a high sensitivity to treatment variations. The field passed if 93% of the pixels had a Gamma of 1 or less. Results: Twenty-nine percent of the fields failed. The average plan passing rate was 92.5%.The average 3D plan passing rate was less than for VMAT or IMRT, 84%, vs. an average of 96.2%. When fields failed, an investigation revealed changes in patient anatomy or setup variations, often also leading to variations of transmission through immobilization devices. Conclusion: PerFRACTION is a fully automated system for determining daily changes in dose transmission through the patient that requires no effort other than for the imager panel to be deployed during treatment. A surprising number of fields failed the analysis and can be attributed to important treatment variations that would otherwise not be appreciated. Further study of inter-fraction treatment variations is possible and warranted. Sun Nuclear Corporation provided a license to the software described.

60 APPLIED LIFE SCIENCES↗

WE-D-BRD-00: New Developments in Hybrid MR-Treatment: Technology

The advantages that make MR highly desirable for in-room treatment guidance, i.e. soft-tissue visualization and physiological assessment of healthy/tumor tissues, are largely recognized in the research community. However, the MR absorption in practical clinical workflows is still hindered by lack of sufficient technological infrastructure. Recent advances have been made towards filling that gap such as the development of integrated therapy systems relying on an MR scanner and a radiation source (linac, Co-60) and/or brachytherapy. The session is intended to present new efforts and methods aimed at facilitating the adoption of MR guidance for treatment delivery. Specifically, the discussion will focus on a) linac designs for reduced footprint and seamless integration with MR/linac systems, b) tracking coils for brachytherapy applications, and c) procedures for the commissioning and monitoring of MR and MR/linac performance. Learning Objectives: Understand limitations and proposed solutions for linac designs and associated integration with MR/linac systems; Understand current issues with MR-guided brachytherapy procedures Understand the issues and needs for new MR commissioning and QC. License agreement with Modus Medical Devices to develop a phantom for the quantification of MR image distortions.

60 APPLIED LIFE SCIENCES↗

WE-D-BRD-01: New Linac Designs for MR-Guided Therapy Systems

The advantages that make MR highly desirable for in-room treatment guidance, i.e. soft-tissue visualization and physiological assessment of healthy/tumor tissues, are largely recognized in the research community. However, the MR absorption in practical clinical workflows is still hindered by lack of sufficient technological infrastructure. Recent advances have been made towards filling that gap such as the development of integrated therapy systems relying on an MR scanner and a radiation source (linac, Co-60) and/or brachytherapy. The session is intended to present new efforts and methods aimed at facilitating the adoption of MR guidance for treatment delivery. Specifically, the discussion will focus on a) linac designs for reduced footprint and seamless integration with MR/linac systems, b) tracking coils for brachytherapy applications, and c) procedures for the commissioning and monitoring of MR and MR/linac performance. Learning Objectives: Understand limitations and proposed solutions for linac designs and associated integration with MR/linac systems; Understand current issues with MR-guided brachytherapy procedures Understand the issues and needs for new MR commissioning and QC. License agreement with Modus Medical Devices to develop a phantom for the quantification of MR image distortions.

60 APPLIED LIFE SCIENCES↗

WE-D-BRD-02: Tracking Coils for Brachy MR Guidance

The advantages that make MR highly desirable for in-room treatment guidance, i.e. soft-tissue visualization and physiological assessment of healthy/tumor tissues, are largely recognized in the research community. However, the MR absorption in practical clinical workflows is still hindered by lack of sufficient technological infrastructure. Recent advances have been made towards filling that gap such as the development of integrated therapy systems relying on an MR scanner and a radiation source (linac, Co-60) and/or brachytherapy. The session is intended to present new efforts and methods aimed at facilitating the adoption of MR guidance for treatment delivery. Specifically, the discussion will focus on a) linac designs for reduced footprint and seamless integration with MR/linac systems, b) tracking coils for brachytherapy applications, and c) procedures for the commissioning and monitoring of MR and MR/linac performance. Learning Objectives: Understand limitations and proposed solutions for linac designs and associated integration with MR/linac systems; Understand current issues with MR-guided brachytherapy procedures Understand the issues and needs for new MR commissioning and QC. License agreement with Modus Medical Devices to develop a phantom for the quantification of MR image distortions.

60 APPLIED LIFE SCIENCES↗

WE-D-BRD-03: Novel Methods and Tools for MR Commissioning and QC

The advantages that make MR highly desirable for in-room treatment guidance, i.e. soft-tissue visualization and physiological assessment of healthy/tumor tissues, are largely recognized in the research community. However, the MR absorption in practical clinical workflows is still hindered by lack of sufficient technological infrastructure. Recent advances have been made towards filling that gap such as the development of integrated therapy systems relying on an MR scanner and a radiation source (linac, Co-60) and/or brachytherapy. The session is intended to present new efforts and methods aimed at facilitating the adoption of MR guidance for treatment delivery. Specifically, the discussion will focus on a) linac designs for reduced footprint and seamless integration with MR/linac systems, b) tracking coils for brachytherapy applications, and c) procedures for the commissioning and monitoring of MR and MR/linac performance. Learning Objectives: Understand limitations and proposed solutions for linac designs and associated integration with MR/linac systems; Understand current issues with MR-guided brachytherapy procedures Understand the issues and needs for new MR commissioning and QC. License agreement with Modus Medical Devices to develop a phantom for the quantification of MR image distortions.

60 APPLIED LIFE SCIENCES↗

SU-F-T-399: Migration of Treatment Planning Systems Without Beam Data Measurement

Purpose: Data acquisition for commissioning is steered by Treatment Planning System (TPS) requirements which can be cumbersome and time consuming involving significant clinic downtime. The purpose of this abstract is to answer if we could circumvent this by extracting data from existing TPS and speed up the process. Methods: Commissioning beam data was obtained from a clinically commissioned TPS (Pinnacle™) using Matlab™ generated Pinnacle™ executable scripts to commission a secondary 3D dose verification TPS (Eclipse™). Profiles and output factors for commissioning as required by Eclipse™ were computed on a 50 cm{sup 3} water phantom at a dose grid resolution of 2mm3. Verification doses were computed and compared to clinical TPS dose profiles as per TG-106 guidelines. Standard patient plans from Pinnacle™ including IMRT and VMAT plans were re-computed keeping the same monitor units (in order to perform true comparison) using Eclipse™. Computed dose was exported back to Pinnacle for comparison to original plans. This methodology enables us to alleviate all ambiguities that arise in such studies. Results: Profile analysis using in-house software for 6x, showed that for all field sizes including small MLC generated fields, 100% of infield and penumbra data points of Eclipse™ match Pinnacle™ generated and measured profiles with 2%/2 mm gamma criteria. Excellent agreement was observed in the penumbra regions, with all data points passing DTA criteria for complex C-shaped and S-shaped profiles. Patient plan dose volume histograms (DVHs) and isodose lines agreed well to within a 1.5% for target coverage. Conclusion: Secondary 3D dose checking is of utmost importance with advanced techniques such as IMRT and VMAT. Migration of TPS is possible without compromising accuracy or enduring the cumbersome measurement of commissioning data. Economizing time for commissioning such a verification system or for migration of TPS can add great QA value and minimize downtime.

60 APPLIED LIFE SCIENCES↗

A Tanks-in-Series Approach to Estimate Parameters for Lithium-Ion Battery Models

Advanced Battery Management Systems (BMS) play a vital role in monitoring, predicting, and controlling the performance of lithium-ion batteries. BMS employing sophisticated electrochemical models can help increase battery cycle life and minimize charging time. However, in order to realize the full potential of electrochemical model-based BMS, it is critical to ensure accurate predictions and proper model parameterization. The accuracy of the predictions of an electrochemical model is dependent on the accuracy of its parameters, the values of which might change with battery cycling and aging. Parameter estimation for an electrochemical model is generally challenging due to the nonlinear nature and computational complexity of the model equations. To this end, this work utilizes the recently proposed Tanks-in-Series model for Li-ion batteries (J.Electrochem. Soc., 167, 013534 (2020)) to perform parameter estimation. The Tanks-in-Series approach allows for substantially faster parameter estimation compared to the original pseudo two-dimensional (p2D) model. The objective of this work is thus to demonstrate the gain in computational efficiency from the Tanks-in-Series approach. A sensitivity analysis of model parameters is also performed to benchmark the fidelity of the Tanks-in-Series model.

25 ENERGY STORAGE↗

Alignment Implementation for Manufacturing using Fringe Analysis Slope Technique (AIMFAST) 2018.11.20

AIMFAST is a software code used to align facets on a dish or heliostat solar concentrator to a specific aimpoint strategy to minimize peak fluxes and maximize system optical performance. AIMFAST uses a large monitor or projection screen to display fringe patterns, and a machine vision camera to image the reflection of these patterns in the subject dish mirrors. From these images, a detailed map of surface normals can be generated and compared to design or fitted mirror shapes. This fitted comparison is then used to develop a single vector representing the orientation of the facets relative to the design orientation and provide near-real-time adjustment information to a communicating computer. The communicating computer can display adjustments or directly interface with adjustment tools.

Yellowhair, Julius↗

Spot-Checking for Reliable Quantum Communications

We demonstrate a spot-checking approach for real-time drift estimation and mitigation in continuously operating quantum links. Using polarization-entangled photon pairs, we achieve stable 16-hour operation, validating efficient, minimally invasive monitoring of quantum-network performance.

Zhang, Yanbao [ORNL] (ORCID:0000000245530561)↗

SEM Grid Testing at NLCTA in BeamNetUS Program

We report on the performance of a secondary electron monitor (SEM) grid used to measure the transverse profile of an MeV range electron beam at SLAC National Accelerator Laboratory’s Next Linear Collider Test Accelerator (NLCTA) facility. When inserted into the path of the electron beam, secondary electron emission results in a measurable current on the wires that make up the grid. We present measurements using this technique to reconstruct the beam profile. The SEM grid was designed and manufactured by a team of undergraduate students at Harvey Mudd College (HMC) and was tested at SLAC’s NLCTA facility in collaboration with NCLTA staff as part of the BeamNetUS program. Developed for real-time diagnostics of MeV-range electron beams, this SEM grid has potential applications in both industrial and medical contexts.

43 PARTICLE ACCELERATORS↗

Spray Foam Exterior Insulation with Stand-Off Furring

IBACOS, in collaboration with GreenHomes America, was contracted by the New York State Energy Research and Development Authority to research exterior wall insulation solutions. This research investigated cost-effective deep energy retrofit (DER) solutions for improving the building shell exterior while achieving a cost-reduction goal, including reduced labor costs to reach a 50/50 split between material and labor. The strategies included exterior wall insulation plus energy upgrades as needed in the attic, mechanical and ventilation systems, and basement band joist, walls, and floors. The work can be integrated with other home improvements such as siding or window replacement. This strategy minimizes physical connections to existing wall studs, encapsulates existing siding materials (including lead paint) with spray foam, and creates a vented rain screen assembly to promote drying. GreenHomes America applied construction details created by IBACOS to a test home. 2x4 framing members were attached to the wall at band joists and top plates using 'L' clips, with spray foam insulating the wall after framing was installed. Windows were installed simultaneously with the framing, including extension jambs. The use of clips in specific areas provided the best strength potential, and 'picture framing' the spray foam held the 2x4s in place. Short-term testing was performed at this house, with monitoring equipment installed for long-term testing. Testing measurements will be provided in a later report, as well as utility impact (before and after), costs (labor and materials), construction time, standard specifications, and analysis for the exterior wall insulation strategy.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Stand-Off Furring in Deep Energy Retrofits: Syracuse, New York (Fact Sheet)

IBACOS, in collaboration with GreenHomes America, was contracted by the New York State Energy Research and Development Authority to research exterior wall insulation solutions. This research investigated cost-effective deep energy retrofit (DER) solutions for improving the building shell exterior while achieving a cost-reduction goal, including reduced labor costs to reach a 50/50 split between material and labor. The strategies included exterior wall insulation plus energy upgrades as needed in the attic, mechanical and ventilation systems, and basement band joist, walls, and floors. The work can be integrated with other home improvements such as siding or window replacement. This strategy minimizes physical connections to existing wall studs, encapsulates existing siding materials (including lead paint) with spray foam, and creates a vented rain screen assembly to promote drying. GreenHomes America applied construction details created by IBACOS to a test home. 2x4 framing members were attached to the wall at band joists and top plates using 'L' clips, with spray foam insulating the wall after framing was installed. Windows were installed simultaneously with the framing, including extension jambs. The use of clips in specific areas provided the best strength potential, and 'picture framing' the spray foam held the 2x4s in place. Short-term testing was performed at this house, with monitoring equipment installed for long-term testing. Testing measurements will be provided in a later report, as well as utility impact (before and after), costs (labor and materials), construction time, standard specifications, and analysis for the exterior wall insulation strategy.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Spray Foam Exterior Insulation with Stand-Off Furring

IBACOS, in collaboration with GreenHomes America, was contracted by the New York State Energy Research and Development Authority to research exterior wall insulation solutions. This research investigated cost-effective deep energy retrofit (DER) solutions for improving the building shell exterior while achieving a cost-reduction goal, including reduced labor costs to reach a 50/50 split between material and labor. The strategies included exterior wall insulation plus energy upgrades as needed in the attic, mechanical and ventilation systems, and basement band joist, walls, and floors. The work can be integrated with other home improvements such as siding or window replacement. This strategy minimizes physical connections to existing wall studs, encapsulates existing siding materials (including lead paint) with spray foam, and creates a vented rain screen assembly to promote drying. GreenHomes America applied construction details created by IBACOS to a test home. 2x4 framing members were attached to the wall at band joists and top plates using "L" clips, with spray foam insulating the wall after framing was installed. Windows were installed simultaneously with the framing, including extension jambs. The use of clips in specific areas provided the best strength potential, and "picture framing" the spray foam held the 2x4s in place. Short-term testing was performed at this house, with monitoring equipment installed for long-term testing. Testing measurements will be provided in a later report, as well as utility impact (before and after), costs (labor and materials), construction time, standard specifications, and analysis for the exterior wall insulation strategy.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Demonstration of thermal control, microstructure control, defect mitigation and process parameter database generation for Ti-6Al-4V Direct Digital Manufacturing - Understanding defect mitigation and process parameter database generation for direct digital manufacturing

Researchers from Manufacturing Demonstration Facility (MDF) at Oak Ridge National Laboratory (ORNL) worked with Applied Optimization (AO) to understand and evaluate the propensity for defect formation in builds manufactured using DM3D-POM laser direct metal deposition. The main aim of this collaboration was to understand the character of powder jet behavior as a function of the nozzle parameters such as cover gas, carrier gas, and shaping gas. In order to evaluate the sensitivities of the parameters used in model, various experiments were performed with in-situ monitoring of the powder stream characteristics using a high speed camera. A wide variety of conditions while keeping the hopper motor rpm constant, including laser power and travel speed were explored. The cross sections of the deposits were characterized using optical microscopy.

47 OTHER INSTRUMENTATION↗

E Tunnel Wastewater Disposal System Quarterly Monitoring Report Nevada National Security Site, Nevada Water Pollution Control Permit NEV 96021, Second Quarter 2018

This report includes the results of the E Tunnel Wastewater Disposal System (ETDS) inspections and monitoring for April, May and June 2018. Monitoring and sampling activities were performed in accordance with the requirements of Water Pollution Control Permit NEV 96021, Revision 1, effective October 1, 2013.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗