Global populations of Pyrenophora teres f. maculata have evolved to target multiple dominant barley susceptibility loci, highlighting the risk of widespread disease under local selection pressures. The necrotrophic fungal pathogen Pyrenophora teres f. maculata causes spot form net blotch (SFNB), a global disease of barley. This fungus uses effector proteins to promote infection, which act in an inverse gene-for-gene manner by targeting dominant host susceptibility genes. Currently, there is a general understanding of the genetics of resistance/susceptibility in the host; however, there are still gaps in our understanding of global pathogen virulence and how it has evolved to target the host and cause disease. Because the P. teres f. maculata-barley interaction conforms to an inverse gene-for-gene model, we crossed three different susceptible barley lines (Hockett, TR 326, and PI 392501) with the resistant line PI 67381 and mapped recombinant inbred populations to characterize the susceptibility in these lines based on their response to ten pathogen isolates collected from diverse barley growing regions on five continents. Four independent quantitative trait loci (QTL) showed associations with susceptibility and mapped to barley chromosomes (Chr) 2HS, 4HS, 4HL, and 7HL. In all three populations, the same genomic position on Chr7HL was associated with the highest susceptibility levels and was targeted by seven of the ten fungal isolates. The QTL identified on Chr2HS mapped to the same position in two populations and was also targeted by seven of the ten isolates. However, the Chr4HS and Chr4HL susceptibilities were targeted by only three and two of the global isolates, respectively. This work shows that pathogen populations under different host selection pressures can evolve to target different barley susceptibility loci.
Validated learning plays a critical role in the lean startup approach to entrepreneurship education. We argue that, compared to validated learning from business generalists, student entrepreneurs who seek feedback from technical specialists develop superior minimum viable products (MVPs). We further suggest that the different effects of feedback from business generalists and technical specialists on the quality of MVPs are mediated by student entrepreneurs' failure analysis. Using a between-subjects, randomized field experiment with a longitudinal design, we find our hypotheses supported. The results indicate that validated learning from technical specialists, in addition to business generalists, should be incorporated into the lean startup pedagogy to guide student entrepreneurs for better MVPs.
The impact of the chemical environment and oxidation state on the X-ray absorption spectra (XAS) of the uranium O4,5 edge has been investigated using quantum simulations and compared with experimental data. The XAS features of UO2Cl2 are simulated using time-dependent density functional theory and validated against experimental measurements. The results demonstrate that good agreement between theory and experiment is achievable by employing generalized gradient approximation DFT with spin-orbit coupling corrections. Building on this validated computational approach, we examine the impact of the oxidation state by comparing U(VI)O2Cl2 and U(IV)Cl6 2-, U(VI)O2Cl2 and U6+, and U(IV)Cl6 2- and U4+. While both U(IV) and U(VI) complexes exhibit similar main edge peaks, distinct differences appear in the pre-edge region. U(VI) exhibits more intense main edge features with greater uranium-ligand orbital mixing while U(IV) shows an enhanced intensity at the main edge and pre-edge. The U(IV) spectrum is red-shifted relative to U(VI), and this was induced by the ligands and change in oxidation states. These results are interpreted by analyzing the orbital plots of hole-electron densities associated with participating electronic transitions. These quantified, system-specific signatures provide practical reference points for distinguishing oxidation state and coordination environment in uranium compounds.
This research endeavors to protect structural steel from corrosion by employing varying concentrations (0%, 1%, 2%, and 3% by wt.) of five biobased polyols (xylitol, erythritol, maltitol, mannitol, and sorbitol) in a crude oil simulant (COS) environment. Steel specimens are corroded in an accelerated manner by exposing them to a dripping flow of COS, containing 1%, 2%, and 3% by wt., of these biobased polyols for a duration of 48 h. Potentiodynamic polarization tests are conducted to quantify the corrosion damage incurred to these specimens. Tafel extrapolation was performed on the polarization curves to determine the corrosion current densities, corrosion rates, and other electrochemical parameters. Visual analysis revealed that all five polyols effectively reduced corrosion damage to steel in the COS environment. The presence of polyols in the COS reduced the corrosion rate by up to 84% and improved the corrosion inhibition efficiency by up to 87%. The adsorption of polyols in the COS environment followed Langmuir adsorption isotherm. The standard free energy of adsorption ranges from -15.71 kJ/mol to -18.50 kJ/mol, suggesting that polyols physisorbed onto the steel surface, reducing both the anodic and cathodic reactions, thereby reducing corrosion damage.
Hard red spring (HRS) wheat is a high-protein class prized for its nutritional value and functional properties in whole grain products. While nitrogen (N) fertilization is known to affect yield and protein content, its influence on antioxidant activity and antinutritional factors remains less explored. This study examined the effects of three N application rates (0, 100, and 150 lb/acre) on grain composition, antioxidant capacity, and phytic acid (PA) content in three HRS wheat varieties grown at multiple locations in North Dakota and Minnesota. Antioxidant capacity was evaluated via total phenolics, flavonoids, and radical scavenging assays (2,2-diphenyl-1-picrylhydrazyl [DPPH], 2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonate) [ABTS], and ferric reducing antioxidant power [FRAP]), while PA was measured as an indicator of antinutritional potential. Application of 150 lb/acre N significantly increased grain protein content (20%-24%, p < .05) and enhanced antioxidant activity, with DPPH, ABTS, and FRAP values rising by 32%, 42%, and 82%, respectively, relative to the control. These increases were associated with elevated levels of free (63%) and bound (53%) phenolics, as well as greater flavonoid accumulation. In contrast, PA content declined significantly, from 8.5 to 5.5 mg/g (p < .05), and was strongly negatively correlated with N rate (r = -0.8). Protein content, phenolics, flavonoids, antioxidant activity, and PA levels were all significantly affected by genotype (G), environment (E), and G & times; E interactions. These findings suggest that optimised N fertilization can simultaneously improve grain protein and antioxidant properties while reducing antinutritional compounds. This targeted agronomic approach offers a promising strategy for producing healthier, nutrient-rich wheat under diverse genotype-environment conditions.
