Heavy Metal Chemistry of Sediments in Caves of the Springfield Plateau, Missouri-Arkansas-Oklahoma: A Link to Subterranean Biodiversity

We used X-ray fluorescence (XRF) to compare the heavy metal chemistry of sediments in caves in rural and urban areas to the chemistry of sediments from a control cave in a relatively undisturbed watershed in the Springfield (MO) Plateau. Sediment from Smallin Cave near Ozark, MO, the control cave, has the smallest peak sizes for Zn and Mn and a moderately-sized Pb peak. Sediment from the rural cave exhibited larger peaks of Zn and Mn and a smaller Pb peak. Sediment from the urban cave had the largest Zn, Mn and Pb peaks. Interestingly, smaller peak sizes appear to correlate to the presence of aquatic troglobites. The control cave hosts the most diverse troglobitic fauna and has sediment with smaller peak sizes. Ruark caves are rural caves, and are barren of troglobites and have sediment with larger peak sizes. Giboney Cave, an urban cave in Doling Park in Springfield, MO, provides the most interesting evidence. Giboney Cave splits into two branches, each of which has a unique chemical fingerprint. One channel is barren of cave life and has sediment that exhibits large metal peaks. The second channel hosts aquatic troglobites and has sediment that has small metal peaks. These findings are of particular importance because the caves of the Springfield Plateau host abundant troglobitic species, including the endangered Ozarks cavefish (Amblyopsis rosae). Sediment metal concentrations may indicate which cave systems are capable of supporting life, with XRF analysis providing a non-destructive, rapid way to identify such systems

Gender Comparisons of Mechanomyographic Amplitude and Mean Power Frequency Versus Isometric Torque Relationships

This is the publisher's version, also found at http://ehis.ebscohost.com/ehost/detail?sid=e7a03093-e666-4634-b895-d6b4313857c2%40sessionmgr13&vid=1&hid=17&bdata=JnNpdGU9ZWhvc3QtbGl2ZQ%3d%3d#db=s3h&AN=15943883This study compared the patterns of mechanomyographic (MMG) amplitude and mean power frequency vs. torque relationships in men and women during isometric muscle actions of the biceps brachii. Seven men (mean age 23.9 ± 3.5 yrs) and 8 women (mean 21.0 ± 1.3 yrs) performed submaximal to maximal isometric muscle actions of the dominant forearm flexors. Following determination of the isometric maximum voluntary contraction (MVC), they randomly performed submaximal step muscle actions in 10% increments from 10% to 90% MVC. Polynomial regression analyses indicated that the MMG amplitude vs. isometric torque relationship for the men was best fit with a cubic model (R2 = 0.983), where MMG amplitude increased slightly from 10% to 20% MVC, increased rapidly from 20% to 80% MVC, and plateaued from 80% to 100% MVC. For the women, MMG amplitude increased linearly (r2 = 0.949) from 10% to 100% MVC. Linear models also provided the best fit for the MMG mean power frequency vs. isometric torque relationship in both the men (r2 = 0.813) and women (r2 = 0.578). The results demonstrated gender differences in the MMG amplitude vs. isometric torque relationship, but similar torque-related patterns for MMG mean power frequency. These findings suggested that the plateau in MMG amplitude at high levels of isometric torque production for the biceps brachii in the men, but not the women, may have been due to greater isometric torque, muscle stiffness, and/or intramuscular fluid pressure in the men, rather than to differences in moto

Structural and Biochemical Studies of Human 4-hydroxy-2-oxoglutarate Aldolase: Implications for Hydroxyproline Metabolism in Primary Hyperoxaluria

4-hydroxy-2-oxoglutarate (HOG) aldolase is a unique enzyme in the hydroxyproline degradation pathway catalyzing the cleavage of HOG to pyruvate and glyoxylate. Mutations in this enzyme are believed to be associated with the excessive production of oxalate in primary hyperoxaluria type 3 (PH3), although no experimental data is available to support this hypothesis. Moreover, the identity, oligomeric state, enzymatic activity, and crystal structure of human HOGA have not been experimentally determined.In this study human HOGA (hHOGA) was identified by mass spectrometry of the mitochondrial enzyme purified from bovine kidney. hHOGA performs a retro-aldol cleavage reaction reminiscent of the trimeric 2-keto-3-deoxy-6-phosphogluconate aldolases. Sequence comparisons, however, show that HOGA is related to the tetrameric, bacterial dihydrodipicolinate synthases, but the reaction direction is reversed. The 1.97 Å resolution crystal structure of hHOGA bound to pyruvate was determined and enabled the modeling of the HOG-Schiff base intermediate and the identification of active site residues. Kinetic analyses of site-directed mutants support the importance of Lys196 as the nucleophile, Tyr168 and Ser77 as components of a proton relay, and Asn78 and Ser198 as unique residues that facilitate substrate binding.The biochemical and structural data presented support that hHOGA utilizes a type I aldolase reaction mechanism, but employs novel residue interactions for substrate binding. A mapping of the PH3 mutations identifies potential rearrangements in either the active site or the tetrameric assembly that would likely cause a loss in activity. Altogether, these data establish a foundation to assess mutant forms of hHOGA and how their activity could be pharmacologically restored

Evidence for the Direct Detection of the Thermal Spectrum of the Non-Transiting Hot Gas Giant HD 88133 b

We target the thermal emission spectrum of the non-transiting gas giant HD 88133 b with high-resolution near-infrared spectroscopy, by treating the planet and its host star as a spectroscopic binary. For sufficiently deep summed flux observations of the star and planet across multiple epochs, it is possible to resolve the signal of the hot gas giant's atmosphere compared to the brighter stellar spectrum, at a level consistent with the aggregate shot noise of the full data set. To do this, we first perform a principal component analysis to remove the contribution of the Earth's atmosphere to the observed spectra. Then, we use a cross-correlation analysis to tease out the spectra of the host star and HD 88133 b to determine its orbit and identify key sources of atmospheric opacity. In total, six epochs of Keck NIRSPEC L band observations and three epochs of Keck NIRSPEC K band observations of the HD 88133 system were obtained. Based on an analysis of the maximum likelihood curves calculated from the multi-epoch cross correlation of the full data set with two atmospheric models, we report the direct detection of the emission spectrum of the non-transiting exoplanet HD 88133 b and measure a radial projection of the Keplerian orbital velocity of 40 $\pm$ 15 km/s, a true mass of 1.02$^{+0.61}_{-0.28}M_J$, a nearly face-on orbital inclination of 15${^{+6}_{-5}}^{\circ}$, and an atmosphere opacity structure at high dispersion dominated by water vapor. This, combined with eleven years of radial velocity measurements of the system, provides the most up-to-date ephemeris for HD 88133.Comment: 9 pages, 6 figures; accepted for publication in Ap

Development of the US3D Code for Advanced Compressible and Reacting Flow Simulations

Aerothermodynamics and hypersonic flows involve complex multi-disciplinary physics, including finite-rate gas-phase kinetics, finite-rate internal energy relaxation, gas-surface interactions with finite-rate oxidation and sublimation, transition to turbulence, large-scale unsteadiness, shock-boundary layer interactions, fluid-structure interactions, and thermal protection system ablation and thermal response. Many of the flows have a large range of length and time scales, requiring large computational grids, implicit time integration, and large solution run times. The University of Minnesota NASA US3D code was designed for the simulation of these complex, highly-coupled flows. It has many of the features of the well-established DPLR code, but uses unstructured grids and has many advanced numerical capabilities and physical models for multi-physics problems. The main capabilities of the code are described, the physical modeling approaches are discussed, the different types of numerical flux functions and time integration approaches are outlined, and the parallelization strategy is overviewed. Comparisons between US3D and the NASA DPLR code are presented, and several advanced simulations are presented to illustrate some of novel features of the code

Reflections on the Evolution of Smart Polymers

© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Since Staudinger\u27s recognition that polymers were long chain molecules with covalent bonds between repeating units, the field has evolved tremendously. In addition to their many structural roles, polymers have been developed to exhibit “smart” stimuli-responsive behavior. This article will describe the evolution of selected classes of smart polymers including those responsive to changes in pH, temperature, light, and mechanical stimuli, as well as self-immolative polymers and their application in drug delivery, sensors, and actuators. It will also highlight key advancements in polymer chemistry that enabled rapid progress over the past ∼20 years. Whether the key achievements were predictable will be discussed, and the extent to which polymer science remains an independent science versus a service tool will be addressed. Finally, some possibilities for the evolution of the field over the next 20–30 years will be described

Nutrient Use and Management Practices on United States Golf Courses

Nutrient use on United States golf courses increases management costs and has the potential to influence ecosystems. Therefore, it is critical to assess nutrient use and management practices to develop and teach best management practices. The objectives of this survey were to measure nutrient use and management practices on United States golf courses in 2021, and to determine if changes occurred since 2006. A survey was developed and distributed via e-mail to 14,033 United States golf facilities, with 1444 responding. From 2006 to 2021, the total projected nitrogen (N), available phosphorus (P2O5), and soluble potash (K2O) applied declined by 41%, 59%, and 54%, to 54,376, 13,761, and 41,386 tons, respectively. These reductions were attributed to course closures, reduced fertilized acres, reduced application rates, and nutrient use restrictions. The percentage of facilities that did not apply P2O5 increased to 21%, which is likely a result of P2O5 application restrictions. Soil testing was associated with greater application rates of N, P2O5, and K2O. Returning clippings, using precision fertilizer applications, reducing turfgrass acreage, and considering N release from soil organic matter were associated with reduced application rates of P2O5. Golf course superintendents have contributed to nationwide reductions in N, P2O5, and K2O, as evidenced by the reduction in fertilized acres and the reduction in nutrient use rates from 2006 to 2021

Survey of Pest Management Practices on US Golf Courses

Integrated pest management (IPM) is an important component of golf course maintenance and includes conventional chemical pesticide use as well as nonchemical cultural management practices. Determining how frequent pest management practices are used on golf courses is critical when developing educational and outreach programs. The objective of this study was to determine the frequency of pest management practices and pesticide mixing and storage facilities on US golf courses. A survey was sent to 14,033 operational US golf facilities with 10% responding. Reliance on all conventional chemical pesticides increased from 2015 to 2021. The reliance on biological control products declined to 14% and reliance on the nonpesticide practice of using plant growth regulators remained equivalent to 2015. The most common pest management practices included monitoring weather patterns and scouting for pests, with 93% of golf facilities reporting the use of both. The use of written IPM and pesticide application plans increased from 44% to 63% of golf facilities between 2015 and 2021, respectively. Generally, mixing and storage facilities remained unchanged from 2015 to 2021. US golf facilities continue to use nonchemical pest management practices, but reliance on chemical pesticides has increased

Groundwater “fast paths” in the Snake River Plain aquifer: Radiogenic isotope ratios as natural groundwater tracers

Preferential flow paths are expected in many groundwater systems and must be located because they can greatly affect contaminant transport. The fundamental characteristics of radiogenic isotope ratios in chemically evolving waters make them highly effective as preferential flow path indicators. These ratios tend to be more easily interpreted than solute-concentration data because their response to water-rock interaction is less complex. We demonstrate this approach with groundwater {sup 87}Sr/{sup 86}Sr ratios in the Snake River Plain aquifer within and near the Idaho National Engineering and Environmental Laboratory. These data reveal slow-flow zones as lower {sup 87}Sr/{sup 86}Sr areas created by prolonged interaction with the host basalts and a relatively fast flowing zone as a high {sup 87}Sr/{sup 86}Sr area