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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,369 records · Page 76
All sourcesNASA NTRSDOE OSTI
NASA NTRS2024

Space Algae-2 Ground and Lunar Analog Studies in Preparation for Long-Duration Propagation of Cyanobacteria in Spaceflight

There are numerous applications for microalgae in spaceflight missions and on Earth, such as oxygen production, carbon dioxide removal, nutrition, wastewater processing, and biofuel production. Space Algae-2 aims to test the genetic stability of Arthrospira platensis, commonly known as spirulina, during six-months of continuous culture on the International Space Station. Long-duration exposure to ionizing radiation and microgravity may impact growth, nutrient composition, and genetic stability. The high protein, vitamin, antioxidant content, and radiation resistance make spirulina a promising candidate for bioregenerative life support systems. A concept of operations was developed to grow and harvest algal biomass in space. Preflight testing experiments optimized conditions for an extended growth period in a gas permeable bioreactor bag. Preflight and post-harvest storage methods were developed in addition to a novel cryopreservation method. After sample return, multi-omics analysis will be conducted to determine the mutation rate, gene expression, and the protein and metabolite profile. The concept of operations for Space Algae-2 was tested during a lunar mission simulation within a semi-controlled environment. During a six-day lunar analog mission at the Hawai’i Space Exploration Analog and Simulation (HI-SEAS) A. platensis was successfully grown using flight-like hardware. The cyanobacteria were harvested and used to supplement bread as an example of spirulina biomass utilization. Overall, the data collected from Space Algae-2 will inform potential bioengineering of spirulina for space and terrestrial applications.

Algae↗
DOE OSTI2021

The oncogenic role of meiosis-specific Aurora kinase C in mitotic cells

Highlights: • AURKC is expressed in meiotic cells and some cancers. • AURKC expression increases cell migration and transformation of human mitotic cells. • Deletion of AURKC in U2OS cells decreases cell migration and soft agar growth. • Transcriptome analysis reveals that AURKC alters the extracellular matrix. Aberrant expression of meiosis-specific genes in cancer has recently emerged as a driver of some cancer formation. Aurora kinase C (AURKC) is a member of the Aurora kinase family of proteins known to regulate chromosome segregation during cell divisions. AURKC is normally expressed in meiotic cells; however, elevated levels of AURKC mRNA and protein are frequently measured in cancer cells. To understand the function of AURKC in cancer cells, expression was induced in noncancerous, human retina pigmented epithelial cells. While AURKC expression did not alter cell proliferation over 72 h, it did increase cell migration and anchorage independent growth in soft agar suggesting an oncogenic role in mitotically dividing cells. To evaluate AURKC as a potential therapeutic target, a frameshift mutation in the gene was introduced in U2OS osteosarcoma cells using CRISPR-Cas9 technology resulting in a premature stop codon. Cancer cells lacking AURKC displayed no change in cell proliferation over 72 h but did migrate less and formed fewer colonies in soft agar. Whole transcriptome sequencing analysis uncovered over 400 differentially expressed genes in U2OS cells with and without AURKC. GO analysis revealed alterations in proteinaceous extracellular matrix genes including COL1A1. These data indicate that therapeutics targeting AURKC could decrease cancer cell metastasis and disease progression. Because AURKC is transcriptionally silenced in normal mitotic cells, its disruption could specifically target cancer cells limiting the toxic side effects associated with current therapeutics.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2016

Predicting Human Cooperation

The Prisoner’s Dilemma has been a subject of extensive research due to its importance in understanding the ever-present tension between individual self-interest and social benefit. A strictly dominant strategy in a Prisoner’s Dilemma (defection), when played by both players, is mutually harmful. Repetition of the Prisoner’s Dilemma can give rise to cooperation as an equilibrium, but defection is as well, and this ambiguity is difficult to resolve. The numerous behavioral experiments investigating the Prisoner’s Dilemma highlight that players often cooperate, but the level of cooperation varies significantly with the specifics of the experimental predicament. We present the first computational model of human behavior in repeated Prisoner’s Dilemma games that unifies the diversity of experimental observations in a systematic and quantitatively reliable manner. Our model relies on data we integrated from many experiments, comprising 168,386 individual decisions. The model is composed of two pieces: the first predicts the first-period action using solely the structural game parameters, while the second predicts dynamic actions using both game parameters and history of play. Our model is successful not merely at fitting the data, but in predicting behavior at multiple scales in experimental designs not used for calibration, using only information about the game structure. As a result, we demonstrate the power of our approach through a simulation analysis revealing how to best promote human cooperation.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

RETRO RX

RETRO Rx is an R&D 100 Gold Award-winning suite of tools that provides a new class of analytics in the space between traditional epidemiological models and unanalyzed spreadsheets of data. Unlike traditional models, these tools provide analysts, scientists, practitioners, and decision makers a way to easily and effectively do sophisticated analyses using a simple user interface. AIDO guides users at the early stages of a disease outbreak by comparing the current parameters to historic outbreaks. RED Alert constructs a broad historical picture of disease incidence (recent outbreak included) to detect disease reemergence at its earliest stages, locally and globally. RETRO Rx compiles data and presents analysis in a clear, concise visual format to support disease mitigation and prevention planning. Both are available currently as web-based apps. A prototype of the RED Alert mobile app with enhanced functionality is available for beta testing and AIDO mobile app development is planned.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2023

In Situ Investigation of Upper Airway Occlusion in Sleep Disordered Breathing Using Ultrasonic Transducer Arrays

This work presents a novel application of ultrasound for the real-time, non-invasive investigation of occlusion of the upper airway during events of obstructive sleep apnea/hypopnea syndrome. It is hypothesized that ultrasonic pulses applied to the neck during apneic events produce spectral and temporal features that can detect apnea occurrence. Theoretical models of ultrasound propagation and an in vitro test were conducted to test this hypothesis in both transmission and reflection modes. Complete specifications and technical details of the system design and fabrication, which is mounted on each subject’s neck, are presented, including the methodology. Nine patients (seven male and two female, mean age of 42 years, with a range of 25 to 56 years, and body mass index 37.6 ± 6.6 kg/m2) were recruited for a full night study, which included simultaneous nocturnal polysomnography for the validation of the results. Nine temporal features and four spectral features were extracted from the envelope of the received pulse waveform. These were used to compute 26 metrics to quantify the changes in the ultrasonic waveforms between normal breathing and apneic events. The statistical analysis of the collected ultrasonic data showed that at least two or more of the proposed features could detect apneic events in all subjects. The findings establish the feasibility of the proposed method as a cost-effective and non-invasive OSAHS screening tool.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2021

Structural insight into host plasma membrane association and assembly of HIV-1 matrix protein

Oligomerization of Pr55 Gag is a critical step of the late stage of the HIV life cycle. It has been known that the binding of IP6, an abundant endogenous cyclitol molecule at the MA domain, has been linked to the oligomerization of Pr55 Gag . However, the exact binding site of IP6 on MA remains unknown and the structural details of this interaction are missing. Here, we present three high-resolution crystal structures of the MA domain in complex with IP6 molecules to reveal its binding mode. Additionally, extensive Differential Scanning Fluorimetry analysis combined with cryo- and ambient-temperature X-ray crystallography and GNM-based transfer entropy calculations identify the key residues that participate in IP6 binding. Our data provide novel insights about the multilayered HIV-1 virion assembly process that involves the interplay of IP6 with PIP2, a phosphoinositide essential for the binding of Pr55 Gag to membrane. IP6 and PIP2 have neighboring alternate binding sites within the same highly basic region (residues 18–33). This indicates that IP6 and PIP2 bindings are not mutually exclusive and may play a key role in coordinating virion particles’ membrane localization. Based on our three different IP6-MA complex crystal structures, we propose a new model that involves IP6 coordination of the oligomerization of outer MA and inner CA domain’s 2D layers during assembly and budding.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2017

A reduced order model to analytically infer atmospheric CO 2 concentration from stomatal and climate data

To address questions related to the acceleration or deceleration of the global hydrological cycle or links between the carbon and water cycles over land, reliable data for past climatic conditions based on proxies are required. In particular, the reconstruction of palaeoatmospheric CO 2 content (C a ) is needed to assist the separation of natural from anthropogenic C a variability and to explore phase relations between C a and air temperature T a time series. Both T a and C a are needed to fingerprint anthropogenic signatures in vapor pressure deficit, a major driver used to explain acceleration or deceleration phases in the global hydrological cycle. Current approaches to C a reconstruction rely on a robust inverse correlation between measured stomatal density in leaves (ν) of many plant taxa and C a . There are two methods that exploit this correlation: The first uses calibration curves obtained from extant species assumed to represent the fossil taxa, thereby restricting the suitable taxa to those existing today. The second is a hybrid eco-hydrological/physiological approach that determines C a with the aid of systems of equations based on quasi-instantaneous leaf-gas exchange theories and fossil stomatal data collected along with other measured leaf anatomical traits and parameters. In this contribution, a reduced order model (ROM) is proposed that derives C a from a single equation incorporating the aforementioned stomatal data, basic climate (e.g. temperature), estimated biochemical parameters of assimilation and isotope data. The usage of the ROM is then illustrated by applying it to isotopic and anatomical measurements from three extant species. The ROM derivation is based on a balance between the biochemical demand and atmospheric supply of CO 2 that leads to an explicit expression linking stomatal conductance to internal CO 2 concentration (C i ) and C a . The resulting expression of stomatal conductance from the carbon economy of the leaf is then equated to another expression derived from water vapor gas diffusion that includes anatomical traits. When combined with isotopic measurements for long-term C i /C a , C a can be analytically determined and is interpreted as the time-averaged C a that existed over the life-span of the leaf. Key advantages of the proposed ROM are: 1) the usage of isotopic data provides constraints on the reconstructed atmospheric CO 2 concentration from ν, 2) the analytical form of this approach permits direct links between parameter uncertainties and reconstructed C a , and 3) the time-scale mismatch between the application of instantaneous leaf-gas exchange expressions constrained with longer-term isotopic data is reconciled through averaging rules and sensitivity analysis. The latter point was rarely considered in prior reconstruction studies that combined models of leaf-gas exchange and isotopic data to reconstruct C a from ν. The proposed ROM is not without its limitations given the need to a priori assume a parameter related to the control on photosynthetic rate. Our work here further explores immanent constraints for the aforementioned photosynthetic parameter.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Life cycle assessment of utilizing freshly cut urban wood: A case study

Large amounts of urban wood resources are generated through tree removals in urban areas. Therefore, there is a growing interest to improve the environmental performance of the urban wood supply chain by quantifying the environmental impacts of creating high-value products from urban tree removals to enhance its utilization. By surveying existing urban wood utilization operations for primary data in two major cities: Baltimore, Maryland, and Milwaukee, Wisconsin, a new life cycle inventory (LCI) dataset per m 3 of dry urban hardwood lumber and live edge slabs was created. Incorporating the new LCI data into life cycle assessment method, the total global warming (GW) impact of converting urban trees to kiln-dried lumber was estimated to be 122 kg CO 2 eq and 336 kg CO 2 eq per m 3 of lumber produced for Baltimore and Milwaukee, respectively. In both cases, the total environmental impact of the product was dominated by the conversion of urban trees to kiln dried lumber at the sawmill processing stage. Using scenario analysis for the source of heat generation used in kiln (force) drying wood, substituting wood fuel from coproducts for natural gas in a boiler for Milwaukee resulted in a substantial reduction in fossil-derived GW impact. Urban and traditional hardwood lumber production follow similar GW impact trajectories over their life-cycle stages with the lumber processing stage having the highest environmental impacts for both. Finally, increasing the overall lumber yield and decreasing kiln (force) drying would substantially improve the environmental performance of urban hardwood lumber and help make it comparable to traditional lumber.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2016

Measurement of the E r c . m . = 259 keV resonance in the N 14 ( p , γ ) O 15 reaction

The N 14 ( p , γ ) O 15 reaction regulates the power generated by the CN cycle and thus impacts the structure and evolution of every star at some point in its life. The lowest positive-energy resonance in this reaction is located at E r c . m . = 259 keV, too high in energy to strongly influence quiescent stellar burning. Yet, the strength of this resonance is used as a cross-section normalization for lower-energy measurements of this reaction. We report on new measurements of the energy, strength, and γ -ray branching ratios for the 259-keV resonance, using different detection and data-analysis schemes. We have also reevaluated previous results, where possible. Our proposed recommended strength of ω γ = 12.6 ( 3 ) meV is in agreement with the previous value of 13.1(6) meV, but is more precise and thus provides a more reliable normalization for low-energy ( p , γ ) measurements.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2016

SU-F-P-03: Management of Time to Treatment Inititation: Case for An Electronic Whiteboard

Purpose: To determine if data mining of an electronic whiteboard improves the management of the Time to Treatment Initiation (TTI) in radiation oncology. Methods: An electronic whiteboard designed to help in managing the planning workflow and improves communication regarding patient planning progress was used to record the dates at which each phase of the planning process began or completed. These are CT Sim date, Plan Start, Physician Review, Physicist Review, Approval for Treatment Delivery, Setup or Verification of Simulation. Results: During clinical implementation, the electronic whiteboard was able to fulfill its primary objective of providing a transparent account of the planning progress of each patient. Peer pressure also meant that individual tasks, such as contouring, were easily brought to the attention of the responsible party and prioritized accordingly. Data mining to analyze the electronic whiteboard per patient (figure 1), per diagnosis (figure 2), per treatment modality (figure 3), per physician (figure 4), per planner (figure 5), etc., added another sophisticated tool in the management of Time to Treatment Initiation without compromising quality of the plans being generated. A longer than necessary time between CT Sim and Plan Start can be discussed among the members of the treatment team as an indication of inadequate/outdated CT Simulator, Contouring Tools, Image Fusion Tools, Other Imaging Studies (MRI, PET/CT) performed, etc. The same for the Plan Start to Physician Review where an extended time than expected may be due unrealistic planning goals, limited planning system features, etc. Conclusion: An Electronic Whiteboard in radiation oncology is not only helping with organizing planning workflow, it is also a potent tool that can be used to reduce the Time to Treatment Initiation by providing the clinic with hard data about the duration of each phase treatment planning as a function of different variable affecting the planning process. The work is supported by the Global Medical Physics Institute.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2024

Fatigue Testing and Characterization of Pre-hydrided Zircaloy-4 Cladding Tubes

The solubility of hydrogen in Zircaloy-4 (Zry-4) at the cladding operating temperature is near 100 wt. ppm. Above this solubility limit, excess hydrogen precipitates as δ-hydride platelets in the cladding material. Because of the effect of the thermal gradient across the cladding thickness on the migration and precipitation of hydrogen, hydride rims are often observed at the cladding outer surface; under excessive corrosion conditions hydride blisters are possible. It is well known that the fatigue of metal alloys, especially high cycle fatigue, is sensitive to the status of surface including the microstructure, roughness, and residual stress. Thus, the question considered herein, is whether excessive hydrogen pickup modifies the microstructure such that it has a degradation effect on the fatigue performance of cladding during operation. This report describes the evaluation of fatigue performance of a pre-hydrided Zry-4 cladding. A commercial Zry-4 was polished and pre-hydrided to 800 ppm and 1300 ppm H contents. The fatigue testing was conducted under strain control at 5 Hz with fully-reversed bending by using a cyclic integrated reversible bending fatigue tester (CIRFT). Six specimens with 1300 ppm and one specimen with 800 ppm were tested. Significant variation in test results were observed. While two of the 1300 ppm specimens failed with less than 1 ×10 5 cycles (at 0.32% and 0.41%), the four other samples did not fail over the strain amplitude range of 0.25% to 0.38%. Interestingly, the fracture initiation site of the failed samples was on the outside diameter (OD) surface rather than on the inside diameter (ID) surface as is typical for the as-polished cladding. This suggested a degrading effect of the hydriding process. Subsequently, three of the unfailed specimens were then further tested at ~0.43% to observe where failure initiation occurred. Significant variation was also observed in these three specimens. One specimen failed at ~9000 cycles while the two others failed at 43000 and 1.06 ×10 5 cycles. The performance here correlated to the location of failure initiation; failure initiated on the OD in the sample that failed after 9000 cycles while it initiated on the ID in the sample that failed after 43000 and 1.06 ×10 5 cycles. Flat features at the OD initiation sites suggest a brittle hydride feature on the surface of those samples was the cause of the degradation in fatigue performance, though the overall hydrogen levels in all samples was similar. A summary of all the observations is provided below: • The un-failed specimens with 1300 ppm H were cycled to failure with a higher amplitude near 0.43%. In addition, the fatigue-treated specimen tended to have a longer fatigue at the same induced amplitude. • Fractography revealed a mixed failure mode for the pre-hydrided specimen. Particularly, the specimen with fracture initiation site (FIS) located on the outer diameter surface of tube tended to have a shorter fatigue life than that of FIS on the inner diameter surface. • Etched cross section was shown to have hydride platelets aligned with tube longitudinal axis as expected, and the density of hydrides is at the similar level as in literature data. Meanwhile, a LECO procedure was applied for hydrogen concentration measurement, which showed the measured hydrogen contents are close to the nominal value. • With the polished cladding tube as baseline, O’Donnell-Lager (O-L) analysis showed that a decrease of about 50% in reduction-of-area (RA) would be needed for the O-L fitting to the fatigue data of 1300 ppm cladding. The suggestion for the next steps is provided.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2026

Technical Basis Update for the Design Life Extension of the SAVY-4000® Series of Containers

This technical basis update focuses on the design life of the SAVY-4000® (hereafter “SAVY”) series of nuclear material storage container (e.g., used to store, transport, and handle special nuclear material outside of a glovebox), previously approved under DOE Manual 441.1-1, Nuclear Material Packaging Manual. The SAVY is approved for storing all authorized contents for a period of 15 years. The lifetime extension technical basis is established on the compiled technical data from the on-going SAVY and Hagan surveillance programs, destructive analysis results, accelerated aging studies, and performance testing, in line with the regulatory rigor of DOE M441.1-1.

42 ENGINEERING↗
NASA NTRS1984

Reliability considerations for the total strain range version of strainrange partitioning

A proposed total strainrange version of strainrange partitioning (SRP) to enhance the manner in which SRP is applied to life prediction is considered with emphasis on how advanced reliability technology can be applied to perform risk analysis and to derive safety check expressions. Uncertainties existing in the design factors associated with life prediction of a component which experiences the combined effects of creep and fatigue can be identified. Examples illustrate how reliability analyses of such a component can be performed when all design factors in the SRP model are random variables reflecting these uncertainties. The Rackwitz-Fiessler and Wu algorithms are used and estimates of the safety index and the probablity of failure are demonstrated for a SRP problem. Methods of analysis of creep-fatigue data with emphasis on procedures for producing synoptic statistics are presented. An attempt to demonstrate the importance of the contribution of the uncertainties associated with small sample sizes (fatique data) to risk estimates is discussed. The procedure for deriving a safety check expression for possible use in a design criteria document is presented.

Wirsching, P. H.↗
NASA NTRS1982

Materials for advanced turbine engines. Project 2: Rene 150 directionally solidified superalloy turbine blades, volume 2

The results of the engine testing of Rene 150 Stage 1 high pressure turbine blades in CF6-50 core and fan engines are presented. The core engine test was conducted for 233 hours with a variety of test cycles, and the fan engine test was conducted for 1000 C cycles. Post-test analysis of the core engine test data confirmed the suitability of the Rene 150 HPT blade for fan engine testing. Post-test evaluation and analysis of the fan engine test blades included visual and dimensional inspection as well as metallographic examination of selected blades. The Rene 150 HPT blade met the target goal of this project by demonstrating increased metal temperature capability; however, the post-test analysis revealed several areas that would have to be addressed in designing a long-life Rene 150 CF6-50 HPT blade.

Deboer, G. J.↗
NASA NTRS2000

A Remote Sensing/Geographic Information Systems Approach in the Selection of Mars Sites of Biological Interest

The search for extinct or extant life on Mars is the search for past or present liquid water, respectively. There are numerous signs of past liquid water on Mars in the form of dry river valleys, paleolakes, and their associated flow and sediment patterns. While some of these features are recent (Amazonian, 1.8 billion years ago to present), there is no evidence that any are currently flowing. Liquid water on the surface would only be possible at those sites with sufficiently high temperatures and pressure. The key to the selection of sites on Mars to search for evidence of life is the search for the presence of water. An approach to this problem is the use of remotely sensed data incorporated in a geographic information system (GIS). A GIS is a computer-based system capable of assembling, storing, manipulating, and displaying geographically referenced information, i.e., data identified according to their locations. In planetary studies these data are acquired from remote sensing (RS) platforms (orbiters). These data are co-registered layers and, through the use of GIS analysis functions, areas on these layers can be selected as a function of the information desired. Our work used existing data layers from the Viking and Mars Global Surveyor missions to determine where water could be possible in liquid form on the Martian surface, based on the phase diagram for water.

Lobitz, B. M.↗
NASA NTRS2016

Evolving Reliability and Maintainability Allocations for NASA Ground Systems

This paper describes the methodology and value of modifying allocations to reliability and maintainability requirements for the NASA Ground Systems Development and Operations (GSDO) program’s subsystems. As systems progressed through their design life cycle and hardware data became available, it became necessary to reexamine the previously derived allocations. This iterative process provided an opportunity for the reliability engineering team to reevaluate allocations as systems moved beyond their conceptual and preliminary design phases. These new allocations are based on updated designs and maintainability characteristics of the components. It was found that trade-offs in reliability and maintainability were essential to ensuring the integrity of the reliability and maintainability analysis. This paper discusses the results of reliability and maintainability reallocations made for the GSDO subsystems as the program nears the end of its design phase.

allocations↗
NASA NTRS2016

Evolving Reliability and Maintainability Allocations for NASA Ground Systems

This paper describes the methodology and value of modifying allocations to reliability and maintainability requirements for the NASA Ground Systems Development and Operations (GSDO) programs subsystems. As systems progressed through their design life cycle and hardware data became available, it became necessary to reexamine the previously derived allocations. This iterative process provided an opportunity for the reliability engineering team to reevaluate allocations as systems moved beyond their conceptual and preliminary design phases. These new allocations are based on updated designs and maintainability characteristics of the components. It was found that trade-offs in reliability and maintainability were essential to ensuring the integrity of the reliability and maintainability analysis. This paper discusses the results of reliability and maintainability reallocations made for the GSDO subsystems as the program nears the end of its design phase.

reliability↗
DOE OSTI2015

Toward a clinical application of ex situ boron neutron capture therapy for lung tumors at the RA-3 reactor in Argentina

Purpose: Many types of lung tumors have a very poor prognosis due to their spread in the whole organ volume. The fact that boron neutron capture therapy (BNCT) would allow for selective targeting of all the nodules regardless of their position, prompted a preclinical feasibility study of ex situ BNCT at the thermal neutron facility of RA-3 reactor in the province of Buenos Aires, Argentina. (L)-4p-dihydroxy-borylphenylalanine fructose complex (BPA-F) biodistribution studies in an adult sheep model and computational dosimetry for a human explanted lung were performed to evaluate the feasibility and the therapeutic potential of ex situ BNCT. Methods: Two kinds of boron biodistribution studies were carried out in the healthy sheep: a set of pharmacokinetic studies without lung excision, and a set that consisted of evaluation of boron concentration in the explanted and perfused lung. In order to assess the feasibility of the clinical application of ex situ BNCT at RA-3, a case of multiple lung metastases was analyzed. A detailed computational representation of the geometry of the lung was built based on a real collapsed human lung. Dosimetric calculations and dose limiting considerations were based on the experimental results from the adult sheep, and on the most suitable information published in the literature. In addition, a workable treatment plan was considered to assess the clinical application in a realistic scenario. Results: Concentration-time profiles for the normal sheep showed that the boron kinetics in blood, lung, and skin would adequately represent the boron behavior and absolute uptake expected in human tissues. Results strongly suggest that the distribution of the boron compound is spatially homogeneous in the lung. A constant lung-to-blood ratio of 1.3 ± 0.1 was observed from 80 min after the end of BPA-F infusion. The fact that this ratio remains constant during time would allow the blood boron concentration to be used as a surrogate and indirect quantification of the estimated value in the explanted healthy lung. The proposed preclinical animal model allowed for the study of the explanted lung. As expected, the boron concentration values fell as a result of the application of the preservation protocol required to preserve the lung function. The distribution of the boron concentration retention factor was obtained for healthy lung, with a mean value of 0.46 ± 0.14 consistent with that reported for metastatic colon carcinoma model in rat perfused lung. Considering the human lung model and suitable tumor control probability for lung cancer, a promising average fraction of controlled lesions higher than 85% was obtained even for a low tumor-to-normal boron concentration ratio of 2. Conclusions: This work reports for the first time data supporting the validity of the ovine model as an adequate human surrogate in terms of boron kinetics and uptake in clinically relevant tissues. Collectively, the results and analysis presented would strongly suggest that ex situ whole lung BNCT irradiation is a feasible and highly promising technique that could greatly contribute to the treatment of metastatic lung disease in those patients without extrapulmonary spread, increasing not only the expected overall survival but also the resulting quality of life.

60 APPLIED LIFE SCIENCES↗