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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 1,477 records · Page 82
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Reply to “Comments on ‘MSE minus CAPE is the True Conserved Variable for an Adiabatically Lifted Parcel’”

A standard convention in moist thermodynamics, adopted by D. M. Romps and others, is to set the specific energy and entropy of dry air and liquid water to zero at the triple-point temperature and pressure. P. Marquet claims that this convention leads to physically incorrect results. To support this claim, Marquet presents numerical calculations of a lifted parcel. It is shown here that the claim is false and that the numerical calculations of Marquet are in error. In the context of a simple two-phase thermodynamic system, an analysis is presented here of the freedoms one has to choose additive constants in the definitions of energy and entropy. Many other misconceptions are corrected as well.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2013

Conservation of the genes for HC-toxin biosynthesis in Alternaria jesenskae

HC-toxin, a cyclic tetrapeptide, is a virulence determinant for the plant pathogenic fungus Cochliobolus carbonum. It was recently discovered that another fungus, Alternaria jesenskae, also produces HC-toxin. The major genes (collectively known as AjTOX2) involved in the biosynthesis of HC-toxin were identified from A. jesenskae by genomic sequencing. The encoded orthologous proteins share 75-85% amino acid identity, and the genes for HC-toxin biosynthesis are duplicated in both fungi. The genomic organization of the genes in the two fungi show a similar but not identical partial clustering arrangement. A set of representative housekeeping proteins show a similar high level of amino acid identity between C. carbonum and A. jesenskae, which is consistent with the close relatedness of these two genera within the family Pleosporaceae (Dothideomycetes).This is the first report that the plant virulence factor HC-toxin is made by an organism other than C. carbonum. The genes may have moved by horizontal transfer between the two species, but it cannot be excluded that they were present in a common ancestor and lost from other species of Alternaria and Cochliobolus

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2014

Multiple conserved regulatory domains promote Fezf2 expression in the developing cerebral cortex

The genetic programs required for development of the cerebral cortex are under intense investigation. However, non-coding DNA elements that control the expression of developmentally important genes remain poorly defined. Here we investigate the regulation of Fezƒ2, a transcription factor that is necessary for the generation of deep-layer cortical projection neurons. Results: Using a combination of chromatin immunoprecipitation followed by high throughput sequencing (ChIP-seq) we mapped the binding of four deep-layer-enriched transcription factors previously shown to be important for cortical development. Building upon this we characterized the activity of three regulatory regions around the Fezƒ2 locus at multiple stages throughout corticogenesis. We identified a promoter that was sufficient for expression in the cerebral cortex, and enhancers that drove reporter gene expression in distinct forebrain domains, including progenitor cells and cortical projection neurons. Conclusions: These results provide insight into the regulatory logic controlling Fezƒ2 expression and further the understanding of how multiple non-coding regulatory domains can collaborate to control gene expression in vivo.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Conserved defense responses between maize and sorghum to Exserohilum turcicum

Abstract Background Exserohilum turcicum is an important pathogen of both sorghum and maize, causing sorghum leaf blight and northern corn leaf blight. Because the same pathogen can infect and cause major losses for two of the most important grain crops, it is an ideal pathosystem to study plant-pathogen evolution and investigate shared resistance mechanisms between the two plant species . To identify sorghum genes involved in the E. turcicum response, we conducted a genome-wide association study (GWAS). Results Using the sorghum conversion panel evaluated across three environments, we identified a total of 216 significant markers. Based on physical linkage with the significant markers, we detected a total of 113 unique candidate genes, some with known roles in plant defense. Also, we compared maize genes known to play a role in resistance to E. turcicum with the association mapping results and found evidence of genes conferring resistance in both crops, providing evidence of shared resistance between maize and sorghum . Conclusions Using a genetics approach, we identified shared genetic regions conferring resistance to E. turcicum in both maize and sorghum. We identified several promising candidate genes for resistance to leaf blight in sorghum, including genes related to R-gene mediated resistance. We present significant advancements in the understanding of host resistance to E. turcicum , which is crucial to reduce losses due to this important pathogen.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2019

Digital Breast Tomosynthesis for Intraoperative Margin Assessment during Breast-Conserving Surgery

Background: Intraoperative margin assessment for breast cancer patients undergoing segmental mastectomy (SM) enables identification of positive margins, with immediate excision of additional tissue to obtain negative margins. Objective: The aim of this study was to determine the ability of digital breast tomosynthesis (DBT) to detect positive margins compared with an institution’s standard extensive processing (SEP). Methods: SM specimens underwent intraoperative SEP with two-dimensional (2D) imaging of the intact and sliced specimen, with review by a breast radiologist and gross assessment by a breast pathologist. Findings guided the surgeon to excise additional tissue. DBT images of intact specimens were prospectively obtained and retrospectively reviewed by a breast radiologist. A positive margin was defined as tumor at ink. Results: Ninety-eight patients underwent 99 SMs. With SEP, 14 (14%) SM specimens had 19 positive margins. SEP did not detect 3 of the 19 positive margins, for a sensitivity of 84%, specificity of 78%, positive predictive value (PPV) of 11%, and negative predictive value (NPV) of 99%. Moreover, DBT did not detect 5 of the 19 positive margins, for a sensitivity of 74% (p > 0.05), specificity of 91% (p < 0.05), PPV of 21.5%, and NPV of 99%. With SEP guidance to excise additional tissue, six cases had final positive margins, with SEP not identifying three of these cases and DBT not identifying two. Pathology from the second surgery of these patients showed either no additional malignancy or only focal ductal carcinoma in situ. Conclusions: DBT is an accurate method for detecting positive margins in breast cancer patients undergoing SM, performing similar to institutional labor-intensive, intraoperative standard processing.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2019

Comparison of Local Recurrence Risk Estimates After Breast-Conserving Surgery for DCIS: DCIS Nomogram Versus Refined Oncotype DX Breast DCIS Score

Background: A ductal carcinoma in situ (DCIS) Nomogram integrating 10 clinicopathologic/treatment factors and a Refined DCIS Score (RDS) that incorporates a genomic assay and three clinicopathologic factors (Oncotype DX DCIS Score) are available to estimate DCIS 10-year local recurrence risk (LRR). This study compared these estimates. Methods: Patients 50 years of age or older with DCIS size 2.5 cm or smaller and a genomic assay available were identified. An RDS within 1–2% of the range of Nomogram LRR estimates obtained by assuming use and non-use of endocrine therapy (Nomogram ± ET) was defined as concordant. Assuming a 10-year risk threshold of 10% for recommending radiation, Nomogram ± ET and RDS estimates were compared, and threshold concordance was determined. Results: For 54 (92%) of 59 patients, the RDS and Nomogram ± ET LRR estimates were concordant. For the remaining 5 (8%) of the 59 patients, the RDS LRR estimates were lower than the Nomogram + ET estimates, with an absolute difference of 3–8%, and thus were discordant. For these five patients, the RDS estimates of 10-year LRR were lower than 10% (range 5–8%) and the Nomogram + ET estimates were 10% or higher (range 11–14%). These five patients with both discordant and threshold-discordant estimates all had close margins (≤ 2 mm). Conclusions: Among 92% of women 50 years of age or older with DCIS size 2.5 cm or smaller, free-of-charge online Nomogram 10-year LRR estimates were concordant with those obtained using the commercially available RDS (> $4600). Among the 8% with discordant risk estimates, the RDS appeared to underestimate the LRR and may lead to inappropriate omission of radiotherapy. Unless other data show a clinically significant advantage of the RDS (Oncotype DX DCIS Score), the study data suggest that for women 50 years of age or older with DCIS size 2.5 cm or smaller, its use is not warranted.

62 RADIOLOGY AND NUCLEAR MEDICINE↗