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At least 1,405 records · Page 78

Light: An Extrinsic Factor Influencing Animal-based Research

Abstract Light is an environmental factor that is extrinsic to animals themselves and that exerts a profound influence on the regulation of circadian, neurohormonal, metabolic, and neurobehavioral systems of all animals, including research animals. These widespread biologic effects of light are mediated by distinct photoreceptors—rods and cones that comprise the conventional visual system and melanopsin-containing intrinsically photosensitive retinal ganglion cells (ipRGCs) of the nonvisual system that interact with the rods and cones. The rods and cones of the visual system, along with the ipRGCs of the nonvisual system, are species distinct in terms of opsins and opsin concentrations and interact with one another to provide vision and regulate circadian rhythms of neurohormonal and neurobehavioral responses to light. Here, we review a brief history of lighting technologies, the nature of light and circadian rhythms, our present understanding of mammalian photoreception, and current industry practices and standards. We also consider the implications of light for vivarium measurement, production, and technological application and provide simple recommendations on artificial lighting for use by regulatory authorities, lighting manufacturers, designers, engineers, researchers, and research animal care staff that ensure best practices for optimizing animal health and well-being and, ultimately, improving scientific outcomes.

Veterinary Sciences↗

Short-Course Accelerated Radiotherapy in Palliative Treatment of Advanced Pelvic Malignancies: A Phase I Study

Purpose: To define the maximum tolerated dose of a conformal short-course accelerated radiotherapy in patients with symptomatic advanced pelvic cancer. Methods and Materials: A phase I trial in 3 dose-escalation steps was designed: 14 Gy (3.5-Gy fractions), 16 Gy (4-Gy fractions), and 18 Gy (4.5-Gy fractions). The eligibility criteria included locally advanced and/or metastatic pelvic cancer and Eastern Cooperative Oncology Group performance status of {<=}3. Treatment was delivered in 2 days with twice-daily fractionation and at least an 8-hour interval. Patients were treated in cohorts of 6-12 to define the maximum tolerated dose. The dose-limiting toxicity was defined as any acute toxicity of grade 3 or greater, using the Radiation Therapy Oncology Group scale. Pain was recorded using a visual analog scale. The effect on quality of life was evaluated according to Cancer Linear Analog Scale (CLAS). Results: Of the 27 enrolled patients, 11 were male and 16 were female, with a median age of 72 years (range 47-86). The primary tumor sites were gynecologic (48%), colorectal (33.5%), and genitourinary (18.5%). The most frequent baseline symptoms were bleeding (48%) and pain (33%). Only grade 1-2 acute toxicities were recorded. No patients experienced dose-limiting toxicity. With a median follow-up time of 6 months (range 3-28), no late toxicities were observed. The overall (complete plus partial) symptom remission was 88.9% (95% confidence interval 66.0%-97.8%). Five patients (41.7%) had complete pain relief, and six (50%) showed >30% visual analog scale reduction. The overall response rate for pain was 91.67% (95% confidence interval 52.4%-99.9%). Conclusions: Conformal short course radiotherapy in twice-daily fractions for 2 consecutive days was well tolerated up to a total dose of 18 Gy. A phase II study is ongoing to confirm the efficacy on symptom control and quality of life indexes.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

Spatial organization of cellulose microfibrils and matrix polysaccharides in primary plant cell walls as imaged by multichannel atomic force microscopy

Summary We used atomic force microscopy ( AFM ), complemented with electron microscopy, to characterize the nanoscale and mesoscale structure of the outer (periclinal) cell wall of onion scale epidermis – a model system for relating wall structure to cell wall mechanics. The epidermal wall contains ~100 lamellae, each ~40 nm thick, containing 3.5‐nm wide cellulose microfibrils oriented in a common direction within a lamella but varying by ~30 to 90° between adjacent lamellae. The wall thus has a crossed polylamellate, not helicoidal, wall structure. Montages of high‐resolution AFM images of the newly deposited wall surface showed that single microfibrils merge into and out of short regions of microfibril bundles, thereby forming a reticulated network. Microfibril direction within a lamella did not change gradually or abruptly across the whole face of the cell, indicating continuity of the lamella across the outer wall. A layer of pectin at the wall surface obscured the underlying cellulose microfibrils when imaged by FESEM , but not by AFM . The AFM thus preferentially detects cellulose microfibrils by probing through the soft matrix in these hydrated walls. AFM ‐based nanomechanical maps revealed significant heterogeneity in cell wall stiffness and adhesiveness at the nm scale. By color coding and merging these maps, the spatial distribution of soft and rigid matrix polymers could be visualized in the context of the stiffer microfibrils. Without chemical extraction and dehydration, our results provide multiscale structural details of the primary cell wall in its near‐native state, with implications for microfibrils motions in different lamellae during uniaxial and biaxial extensions.

Zhang, Tian↗

Systematic calibration of an integrated x-ray and optical tomography system for preclinical radiation research

Purpose: The cone beam computed tomography (CBCT) guided small animal radiation research platform (SARRP) has been developed for focal tumor irradiation, allowing laboratory researchers to test basic biological hypotheses that can modify radiotherapy outcomes in ways that were not feasible previously. CBCT provides excellent bone to soft tissue contrast, but is incapable of differentiating tumors from surrounding soft tissue. Bioluminescence tomography (BLT), in contrast, allows direct visualization of even subpalpable tumors and quantitative evaluation of tumor response. Integration of BLT with CBCT offers complementary image information, with CBCT delineating anatomic structures and BLT differentiating luminescent tumors. This study is to develop a systematic method to calibrate an integrated CBCT and BLT imaging system which can be adopted onboard the SARRP to guide focal tumor irradiation. Methods: The integrated imaging system consists of CBCT, diffuse optical tomography (DOT), and BLT. The anatomy acquired from CBCT and optical properties acquired from DOT serve as a priori information for the subsequent BLT reconstruction. Phantoms were designed and procedures were developed to calibrate the CBCT, DOT/BLT, and the entire integrated system. Geometrical calibration was performed to calibrate the CBCT system. Flat field correction was performed to correct the nonuniform response of the optical imaging system. Absolute emittance calibration was performed to convert the camera readout to the emittance at the phantom or animal surface, which enabled the direct reconstruction of the bioluminescence source strength. Phantom and mouse imaging were performed to validate the calibration. Results: All calibration procedures were successfully performed. Both CBCT of a thin wire and a euthanized mouse revealed no spatial artifact, validating the accuracy of the CBCT calibration. The absolute emittance calibration was validated with a 650 nm laser source, resulting in a 3.0% difference between simulated and measured signal. The calibration of the entire system was confirmed through the CBCT and BLT reconstruction of a bioluminescence source placed inside a tissue-simulating optical phantom. Using a spatial region constraint, the source position was reconstructed with less than 1 mm error and the source strength reconstructed with less than 24% error. Conclusions: A practical and systematic method has been developed to calibrate an integrated x-ray and optical tomography imaging system, including the respective CBCT and optical tomography system calibration and the geometrical calibration of the entire system. The method can be modified and adopted to calibrate CBCT and optical tomography systems that are operated independently or hybrid x-ray and optical tomography imaging systems.

60 APPLIED LIFE SCIENCES↗

TU-H-CAMPUS-IeP2-05: Breast and Soft Tissue-Equivalent 3D Printed Phantoms for Imaging and Dosimetry

Purpose: The study has the goal to demonstrate that breast and soft tissue-equivalent phantoms for dosimetry applications in the diagnostic energy range can be fabricated using common 3D printing methods. Methods: 3D printing provides the opportunity to rapidly prototype uniquely designed objects from a variety of materials. Common 3D printers are usually limited to printing objects based on thermoplastic materials such as PLA, or ABS. The most commonly available plastic is PLA, which has a density significantly greater than soft tissue. We utilized a popular 3D printer to demonstrate that tissue specific phantom materials can be generated through the careful selection of 3D printing parameters. A series of stepwedges were designed and printed using a Makerbot Replicator2 3D printing system. The print file provides custom adjustment of the infill density, orientation and position of the object on the printer stage, selection of infill patterns, and other control parameters. The x-ray attenuation and uniformity of fabricated phantoms were evaluated and compared to common tissue-equivalent phantom materials, acrylic and BR12. X-ray exposure measurements were made using narrow beam geometry on a clinical mammography unit at 28 kVp on the series of phantoms. The 3D printed phantoms were imaged at 28 kVp to visualize the internal structure and uniformity in different planes of the phantoms. Results: By utilizing specific in-fill density and patterns we are able to produce a phantom closely matching the attenuation characteristics of BR12 at 28 kVp. The in-fill patterns used are heterogeneous, so a judicious selection of fill pattern and the orientation of the fill pattern must be made in order to obtain homogenous attenuation along the intended direction of beam propagation. Conclusions: By careful manipulation of the printing parameters, breast and soft tissue-equivalent phantoms appropriate for use at imaging energies can be fabricated using 3D printing techniques.

60 APPLIED LIFE SCIENCES↗

Glovebox Advanced Casting System Casting Optimization

Casting optimization in the GACS included three broad areas; casting of U-10Zr pins, incorporation of an integral FCCI barrier, and development of a permanent crucible coating. U-10Zr casting was improved over last year’s results by modifying the crucible design to minimize contact with the colder mold. Through these modifications casting of a three pin batch was successful. Incorporation of an integral FCCI barrier also was optimized through furnace chamber pressure changes during the casting cycle to reduce gas pressures in the mold cavities which led to three full length pins being cast which incorporated FCCI barriers of three different thicknesses. Permanent crucible coatings were tested against a base case; 1500°C for 10 minutes in a U-20Pu-10Zr molten alloy. None of the candidate coating materials showed evidence of failure upon initial visual examination. In all areas of work a large amount of characterization will be needed to fully determine the effects of the optimization activities. The characterization activities and future work will occur next year.

36 MATERIALS SCIENCE↗

E3SM Water Cycle Visualization Project (Final Report)

Motivated by the need to improve visualizations of Earth's complex water cycle, this team embarked on non-trivial tasks to push from traditional methods of viewing data from simulations as static line graphs and contour plots into new realms with multiple dimensions (three spatial dimensions and the time component) viewable at once. To do this, we chose to feature the extremes in the general circulation of the atmosphere because these Earth system elements are short-lived, but impactful events. We used simulation data produced by the Department of Energy's (DOE) Energy Exascale Earth System Model (E3SM),which is designed to answer DOE science questions using DOE computing facilities. The E3SM project includes three sets of simulation experiments: cryosphere, bio-geochemical cycles, and the water cycle. The water cycle experiment campaign includes a set of simulations designed to understand how the water cycle will change in coming decades under a changing climate.

54 ENVIRONMENTAL SCIENCES↗

Waste Retrieval and Inspection Operations in Hanford Tank 241-AY-102 - 18234

In August 2012, a periodic annulus inspection of tank 241-AY-102 (AY-102) identified a leak from the primary tank into the secondary containment. A pumping plan was developed in 2013 to provide a path forward for recommended remediation actions to be implemented as part of the AY-102 Recovery Project. On March 21, 2014, the Washington State Department of Ecology issued an Administrative Order requiring Washington River Protection Solutions and the United States Department of Energy to conduct actions related to and including the removal of waste from AY-102. The parties agreed to resolve the appeal of the Administrative Order through a Settlement Agreement which addressed the remaining requirements and implemented enforceable milestone dates, including completion of waste removal operations, and performance of an inspection aimed at determining the cause of the leak. The AY-102 Recovery Project was developed to address the Settlement Agreement requirements. While retrieval of waste from Single-Shell Tanks has been performed at Hanford for decades, retrieval from Double-Shell Tank AY-102 required adaptation of the existing technologies to a new environment on a larger scale than previously encountered. Despite countless challenges and obstacles encountered throughout, the project successfully completed system design, fabrication, installation, testing, and retrieval operations within a highly compressed, aggressive schedule. Waste removal activities in AY-102 completed in February 2017. Subsequent inspection activities were completed as part of a multi-step process aimed at determining the likely cause of failure and assessing the feasibility of repair. A variety of input data were used in evaluating the likely failure mechanism, such as video examinations that revealed numerous through-floor penetrations and significant degradation across the visible surface area. Based on the operational history of the tank, corrosion testing and analysis, and the visual appearance of the confirmed leak sites, service-induced pitting corrosion due to the historic waste composition and operating conditions appears to be the primary degradation mechanism leading to failure of the tank. The inspection data has demonstrated that repairing and returning AY-102 to service would likely introduce substantial technical, logistical, and financial challenges due to the extent of bottom-plate damage. As a result, tank AY-102 will ultimately be closed. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

Collaborative: in situ visual analytics technologies for extreme scale combustion simulations

This project aims to drastically enhance the usability of in situ analysis and visualization for extreme-scale scientific simulations. Current exascale computing capabilities promise to offer greater predictive ability of simulations and to further push the frontiers of science and technology. However, to validate the simulation output at extreme scale, examine the modeled phenomena, and discover previously unknowns from the output data, the output must be reduced or transformed in situ as it is being generated during the simulation such that the amount of data to examine and store is kept to a minimum. Such in situ approaches allow us to process and analyze the data and any embedded geometry to an extent that would be prohibitively expensive, if not impossible, to perform as a post hoc task. While in situ processing has been demonstrated to be a feasible and promising approach, its full potential has not yet been leveraged. In this project, we have developed comprehensive enhancements to in situ technology based on probability distributions in data. Our research focuses on jointly developing new ways of interacting with massive statistical samples while creatively utilizing new state-of-the-art computational resources to push the boundaries of in situ exploration. Moreover, we have developed new time-dependent techniques to enable previously unattainable capabilities in areas such as intelligent simulation steering and precise feature identification. We have experimentally studied our design and implementation at NERSC and OLCF, and are able to leverage existing in situ infrastructures whenever possible. While the exemplar in this project is combustion, many other fields for which turbulent transport is important, e.g., fusion, climate, astrophysics among others, encounter similar issues as simulations scale up to the exascale. This project shows its potential to generate high impact on DOE missions since the resulting technology promises to improve scientists’ ability to rapidly and correctly interpret and tune extreme-scale simulations, leading to new scientific understanding and advancements.

97 MATHEMATICS AND COMPUTING↗

Towards Interactive, Reproducible Analytics at Scale on HPC Systems

The growth in scientific data volumes has resulted in a need to scale up processing and analysis pipelines using High Performance Computing (HPC) systems. These workflows need interactive, reproducible analytics at scale. The Jupyter platform provides core capabilities for interactivity but was not designed for HPC systems. In this paper, we outline our efforts that bring together core technologies based on the Jupyter Platform to create interactive, reproducible analytics at scale on HPC systems. Our work is grounded in a real world science use case-applying geophysical simulations and inversions for imaging the subsurface. Our core platform addresses three key areas of the scientific analysis workflow-reproducibility, scalability, and interactivity. We describe our implemention of a system, using Binder, Science Capsule, and Dask software. We demonstrate the use of this software to run our use case and interactively visualize real-Time streams of HDF5 data.

containers↗

CELAVI (Circular Economy Lifecycle Assessment and VIsualization) [SWR-20-87]

A circular economy emphasizes the efficient use of all resources (e.g., materials, land, water). Despite anticipated overall benefits to society, the transition to a circular economy is likely to create regional differences in impacts. Current tools are unable to fully evaluate these potential externalities, which will be important for informing research prioritization and regional decision making. The Circular Economy Lifecycle Assessment and VIsualization (CELAVI) framework allows stakeholders to quantify and visualize potential regional and sectoral transfers of impacts that could result from transitioning to a circular economy, with particular focus on energy materials. The framework uses system dynamics to model material flows for multiple circular economy pathways and decisions are based on learning-by-doing and are implemented via cost and strategic value of different circular economy pathways. It uses network theory to track the spatial and sectoral flow of functional units across a graph and discrete event simulation to to step through time and evaluate lifecycle assessment data at each time step. The framework is designed to be flexible and scalable to accommodate multiple energy materials and multiple energy technologies. The primary goal of CELAVI is to help answer questions about how material flows and environmental and economic impacts of energy systems might change if the circularity of energy systems increases.

Eberle, Annika↗

CELAVI (Circular Economy Lifecycle Assessment and VIsualization) v.1.3.1 9/30/2022 [SWR-20-87]

A circular economy emphasizes the efficient use of all resources (e.g., materials, land, water). Despite anticipated overall benefits to society, the transition to a circular economy is likely to create regional differences in impacts. Current tools are unable to fully evaluate these potential externalities, which will be important for informing research prioritization and regional decision making. The Circular Economy Lifecycle Assessment and VIsualization (CELAVI) framework allows stakeholders to quantify and visualize potential regional and sectoral transfers of impacts that could result from transitioning to a circular economy, with particular focus on energy materials. The framework uses system dynamics to model material flows for multiple circular economy pathways and decisions are based on learning-by-doing and are implemented via cost and strategic value of different circular economy pathways. It uses network theory to track the spatial and sectoral flow of functional units across a graph and discrete event simulation to to step through time and evaluate lifecycle assessment data at each time step. The framework is designed to be flexible and scalable to accommodate multiple energy materials and multiple energy technologies. The primary goal of CELAVI is to help answer questions about how material flows and environmental and economic impacts of energy systems might change if the circularity of energy systems increases.

Eberle, Annika↗

Heat Transfer Efficiency in Various Prandtl Number Turbulent Flows using DNS approach

Convective heat transfer in turbulent flows utilized in many nuclear reactor designs with various coolants. While the traditional light water reactors (LWR) rely on water coolant, some advanced next-generation designs propose to use gas, molten salt, liquid metal coolants. Due to large presence of LWRs, most of the convective heat transfer correlations are focused on fluids with properties similar to water. However, some of the next-generation reactor designs cannot directly apply those correlations to advanced coolants, such as liquid metal, which has very low Prandtl number. Direct Numerical Simulation (DNS) is one of the promising approaches to study the details of fluid flow and heat transfer using first principles. The advances of high performance computing (HPC) in recent years made it possible to apply DNS to a wide variety of flow conditions. Kim and Moin studied heat transfer in fully developed turbulent channel flow using DNS. Kawamura et al. investigated the turbulent heat transfer in channel flow with low to medium-high Prandtl number fluid (ranging between 0.025 and 5.0). They take Reynolds number effects into consideration as well. However, most of these studies focus on medium and high Prandtl number. Low Prandtl number flow (like liquid metal) DNS studies are very limited. In the presented research the effect of low Prandtl number is studied in the turbulent channel flow. The second-order accurate spatial and time discretization is used for the flow solver in the presented work. The instantaneous velocity and temperature fields are visualized in the simulation. The effect of Prandtl number on the heat transfer is investigated by comparing different turbulent flow cases. In the same hydrodynamic conditions, the heat conduction enhances as the Prandtl number decreases in the low Prandtl number range. The behavior of the thermal boundary layer follows the empirical correlation. As the Prandtl number decreases, the conductive sublayer region becomes wider, where is out of the range of the empirical correlation. In the future work, we plan to estimate the Nusselt number as well to compare the total heat transfer rate with respect to different Prandtl number flow, especially the very low Prandtl number cases.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗

Phase 1 Development Report for the SESSA Toolkit.

The Site Exploitation System for Situational Awareness ( SESSA ) tool kit , developed by Sandia National Laboratories (SNL) , is a comprehensive de cision support system for crime scene data acquisition and Sensitive Site Exploitation (SSE). SESSA is an outgrowth of another SNL developed decision support system , the Building R estoration Operations Optimization Model (BROOM), a hardware/software solution for data acquisition, data management, and data analysis. SESSA was designed to meet forensic crime scene needs as defined by the DoD's Military Criminal Investigation Organiza tion (MCIO) . SESSA is a very comprehensive toolki t with a considerable amount of database information managed through a Microsoft SQL (Structured Query Language) database engine, a Geographical Information System (GIS) engine that provides comprehensive m apping capabilities, as well as a an intuitive Graphical User Interface (GUI) . An electronic sketch pad module is included. The system also has the ability to efficiently generate necessary forms for forensic crime scene investigations (e.g., evidence submittal, laboratory requests, and scene notes). SESSA allows the user to capture photos on site, and can read and generate ba rcode labels that limit transcription errors. SESSA runs on PC computers running Windows 7, but is optimized for touch - screen tablet computers running Windows for ease of use at crime scenes and on SSE deployments. A prototype system for 3 - dimensional (3 D) mapping and measur e ments was also developed to complement the SESSA software. The mapping system employs a visual/ depth sensor that captures data to create 3D visualizations of an interior space and to make distance measurements with centimeter - level a ccuracy. Output of this 3D Model Builder module provides a virtual 3D %22walk - through%22 of a crime scene. The 3D mapping system is much less expensive and easier to use than competitive systems. This document covers the basic installation and operation of th e SESSA tool kit in order to give the user enough information to start using the tool kit . SESSA is currently a prototype system and this documentation covers the initial release of the tool kit . Funding for SESSA was provided by the Department of Defense (D oD), Assistant Secretary of Defense for Research and Engineering (ASD(R&E)) Rapid Fielding (RF) organization. The project was managed by the Defense Forensic Science Center (DFSC) , formerly known as the U.S. Army Criminal Investigation Laboratory (USACIL) . ACKNOWLEDGEMENTS The authors wish to acknowledge the funding support for the development of the Site Exploitation System for Situational Awareness (SESSA) toolkit from the Department of Defense (DoD), Assistant Secretary of Defense for Research and Engineering (ASD(R&E)) Rapid Fielding (RF) organization. The project was managed by the Defense Forensic Science Center (DFSC) , formerly known as the U.S. Army Criminal Investigation Laboratory (USACIL). Special thanks to Mr. Garold Warner, of DFSC, who served as the Project Manager. Individuals that worked on the design, functional attributes, algorithm development, system arc hitecture, and software programming include: Robert Knowlton, Brad Melton, Robert Anderson, and Wendy Amai.

Knowlton, Robert G.↗

The His-tag as a decoy modulating preferred orientation in cryoEM

The His-tag is a widely used affinity tag that facilitates purification by means of affinity chromatography of recombinant proteins for functional and structural studies. We show here that His-tag presence affects how coproheme decarboxylase interacts with the air-water interface during grid preparation for cryoEM. Depending on His-tag presence or absence, we observe significant changes in patterns of preferred orientation. Our analysis of particle orientations suggests that His-tag presence can mask the hydrophobic and hydrophilic patches on a protein’s surface that mediate the interactions with the air-water interface, while the hydrophobic linker between a His-tag and the coding sequence of the protein may enhance other interactions with the air-water interface. Our observations suggest that tagging, including rational design of the linkers between an affinity tag and a protein of interest, offer a promising approach to modulating interactions with the air-water interface.

59 BASIC BIOLOGICAL SCIENCES↗

Evolution of highly multimodal Rayleigh–Taylor instabilities

Rayleigh–Taylor (RT) instabilities are important fluid instabilities that arise in inertial confinement fusion (ICF) capsule implosions, and many other contexts. Multi-mode coupling is observed in experiments and plays a substantial role in material mix from RT instabilities. In this work, we study the evolution of highly multimodal perturbations (power law distribution) that approximate those found at manufactured material interfaces. We use simulations of over 2000 different perturbations in the LANL code xRAGE to identify distinct phases in the processes of bubble growth and bubble merger which can be visualized in a 2D phase portrait with clear regimes of mode growth and decay. Our results show that the dynamic evolution of the instability strongly depends on the mode of the perturbations and mode interactions. The merger process accelerates bubble growth. A non-Markovian region and a transition of the instability from: (1) initial exponential growth to (2) linear growth and to (3) quadratic growth and asymptotic behavior, are clearly captured in the phase space. We have developed a quantitative model of bubble growth that reproduces the dynamic behavior of ensembles of perturbations. Implications for ICF capsules designed for robustness against instabilities are discussed.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗

18F-fluorodeoxyglucose Positron Emisson Tomography/Computed Tomography Guided Conformal Brachytherapy for Cervical Cancer

Purpose: To evaluate the feasibility of 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT)-guided conformal brachytherapy treatment planning in patients with cervical cancer. Methods and Materials: Pretreatment FDG-PET/CT was performed for 12 patients with cervical cancer. Brachytherapy simulation was performed after an external-beam radiation therapy median dose of 4140 cGy. Patients underwent FDG-PET/CT scans with placement of tandem and ovoid applicators. The gross tumor volume (GTV) was determined by adjusting the window and level to a reasonable value and outlining the edge of the enhancing area, which was done in consultation with a nuclear medicine physician. A standardized uptake value profile of the tumor margin was taken for each patient relative to the maximum uptake value of each tumor and analyzed. The plan was designed to deliver 400 cGy to point A (point A plan) or to cover the clinical target volume (CTV) (PET/CT plan). Results: The median dose that encompassed 95% of the target volume (D95) of the CTV was 323.0 cGy for the point A plan vs 399.0 cGy for the PET/CT plan (P=.001). The maximum standardized uptake values (SUV{sub max}) of the tumors were reduced by a median of 57% (range, 13%-80%). All but 1 patient presented with discernable residual uptake within the tumors. The median value of the thresholds of the tumors contoured by simple visual analysis was 41% (range, 23%-71%). Conclusions: In this study, the PET/CT plan was better than the conventional point A plan in terms of target coverage without increasing the dose to the normal tissue, making optimized 3-dimensional brachytherapy treatment planning possible. In comparison with the previously reported study with PET or CT alone, we found that visual target localization was facilitated by PET fusion on indeterminate CT masses. Further studies are needed to characterize the metabolic activity detected during radiation therapy for more reliable targeting.

62 RADIOLOGY AND NUCLEAR MEDICINE↗

rcsb-api : Python Toolkit for Streamlining Access to RCSB Protein Data Bank APIs

The Protein Data Bank (PDB) was founded in 1971 as the first open-access digital data resource in biology to serve as the single global archive for three-dimensional (3D) macromolecular structure data. Current PDB holdings exceed 230,000 experimentally determined structures of proteins, nucleic acids, viruses, and macromolecular machines. The RCSB Protein Data Bank RCSB.org research-focused web portal facilitates search, analyses, and visualization of every PDB structure along with more than one million Computed Structure Models from AlphaFold DB and the ModelArchive. It is powered by a set of publicly available Application Programming Interfaces (APIs) that both support RCSB.org users and provide programmatic access to PDB data. Given the breadth and levels of granularity encompassed in this rich data collection, efficiently accessing the information programmatically may be challenging for new users. RCSB PDB has developed a Python software package, rcsb-api , that facilitates easy and efficient use of RCSB PDB APIs within a Python environment. This software tool is designed to streamline access to the extensive corpus of data housed within the PDB, enabling researchers to search, retrieve, and analyze 3D biostructure data seamlessly. Its use will accelerate research in structural biology, molecular biology and biochemistry, drug discovery, and bioinformatics by providing more efficient tools for data integration and analysis. The new toolkit is available on GitHub (github.com/rcsb/py-rcsb-api) and published to the public Python package repository (PyPI) to foster wider usage and support basic and applied research in fundamental biology, biomedicine, and the energy sciences.

FAIR principles↗