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In this study, the fatigue behavior of a semi-crystalline thermoplastic polyether ether ketone (PEEK) is investigated. A series of tests at ambient temperature, including uniaxial monotonic (tension and compression) at different strain rates and uniaxial fully-reversed strain-controlled cyclic tests at strain amplitudes ranging from 0.02 mm/mm to 0.04 mm/mm at various frequencies, were conducted. The frequency influence on the strain-controlled fatigue lives of unfilled PEEK specimens was found to be highly dependent on the strain level. A minimal frequency effect was observed at a lower strain amplitude of 0.02 mm/mm, whereas increasing the test frequency at higher strain amplitudes resulted in longer fatigue lives. Additionally, load-controlled cyclic tests that utilized applied loads corresponding to stress responses obtained from the strain-controlled fatigue tests were performed. The cyclic behavior under the two control modes were compared and discussed. Three types of fatigue models, including a strain-based (Coffin–Manson) model, a strain–stress-based (Smith–Watson–Topper) model, and an energy-based model, were employed to correlate the data in this study. Among the three fatigue models, the energy approach was found to better correlate the PEEK experimental data at various frequencies.

The strain rate, stress state, and temperature dependent mechanical behavior of a hot rolled aluminum 7085-T711 alloy is experimentally observed and subsequently modeled using a continuum Internal State Variable (ISV) plasticity-damage constitutive model. Structure-property relationships for the alloy are quantified using a series of microstructural analyses and mechanical property experiments. The calibrated ISV model for the Al 7085-T711 alloy is implemented in an implicit finite element code (Abaqus) to simulate the deformation of notch Bridgman tension specimens at a variety of stress states and temperatures. The ISV model accurately captures the material's elastoplastic behavior by predicting the stress state difference between tension, compression, and torsion and temperature dependent microstructure evolution under large deformations.

Through in situ electron backscatter diffraction (EBSD) experiments, this paper uncovers dominant damage mechanisms in traditional magnesium alloys exhibiting deformation twinning. The findings emphasize the level of deleterious strain incompatibility induced by twin interaction with other deformation modes and microstructural defects. A double fiber obtained by plane-strain extrusion as a starting texture of AM30 magnesium alloy offered the opportunity to track deformation by EBSD in neighboring grains where some undergo profuse 10-12 twinning and others do not. For a tensile loading applied along extrusion transverse (ET) direction, those experiencing profuse twinning reveal a major effect of grain boundaries on non-Schmid behavior affecting twin variant selection and growth. Similarly, a neighboring grain, with its &lt, c&gt, axis oriented nearly perpendicular to tensile loading, showed an abnormally early nucleation of 10-11 contraction twins (2% strain) while the same 10-11 twin mode triggering under &lt, axis uniaxial compression have higher value of critical resolved shear stress exceeding the values for pyramidal &lt, c+a&gt, dislocations. The difference in nucleation behavior of contraction vs. compression 10-11 twins is attributed to the hydrostatic stresses that promote the required atomic shuffles at the core of twinning disconnections.

There is a known negative association between cytosine–adenine–guanine (CAG) repeat length and the age of motor onset (AMO) in adult-onset Huntington’s Disease (AOHD). This relationship is less clear in patients with juvenile-onset Huntington’s disease (JOHD), however, given the rarity of this patient population. The aim of this study was to investigate this relationship amongst a relatively large group of patients with JOHD using data from the Kids-JOHD study. Additionally, we analyzed data from the Enroll-HD platform and the Predict-HD study to compare the relationship between CAG repeat length and AMO amongst patients with AOHD to that amongst patients with JOHD using linear regression models. In line with previous reports, the variance in AMO that was predicted by CAG repeat length was 59% (p < 0.0001) in the Predict-HD study and 57% from the Enroll-HD platform (p < 0.0001). However, CAG repeat length predicted 84% of the variance in AMO amongst participants from the Kids-JOHD study (p < 0.0001). These results indicate that there may be a stronger relationship between CAG repeat length and AMO in patients with JOHD as compared to patients with AOHD. These results provide additional information that may help to model disease progression of JOHD, which is beneficial for the planning and implementation of future clinical trials.

Introduction: A tumor's blood supply and interstitial flow play an essential role in tumor growth, invasion, and treatment response. We have developed a methodology that employs quantitative MRI data to constrain a patient-specific, computational fluid dynamics (CFD) model of blood flow and interstitial transport within breast tumors. The dynamics of solute transport are characterized based on steady state flow fields, so that delivery of oxygen, nutrients, or therapies through the circulation can be estimated. It is a fundamentally new way to characterize breast tumor hemodynamics using MRI. Method: Eleven malignant and five benign lesions from 12 patients were included in this study. Vessel segmentation and tracking were performed to reconstruct the whole breast vasculature and to identify vessels feeding or draining tumors. Ultrafast dynamic contrast-enhanced MRI and diffusion-weighted imaging data were analyzed to estimate the bolus arrival time, Ktrans (volume transfer coefficient), and ADC (apparent diffusion coefficient); these data were used to spatially assign flow direction, local vascular permeability, and tissue density, respectively. The model of steady state flow was described by three components: 1) blood flow following Poiseuille's law, 2) interstitial flow following Darcy's law, and 3) flux transmitted across the vascular walls following Starling's law. The behavior of drug delivery was described by an advection-diffusion equation in the interstitial tissue, with the profile of the vascular bolus as a source term. The whole system was solved with a 1D-3D coupled implementation. At the end of analysis, the tracer's propagation through the tissue-of-interest was visualized and hemodynamic characteristics are derived to compare the malignant and benign lesions. Result: Visualization of the time-resolved distribution and propagation of solute demonstrated the intratumoral heterogeneity of accessibility to drugs. Furthermore, we are currently calculating the spatially-resolved accumulation, wash-in rate, and infiltration duration of different drugs for each lesion, so that a quantitative comparison can be performed between malignant and benign lesions. Conclusion: We have developed a computational model, informed by patient-specific MRI data, to simulate the blood supply, interstitial fluid environment, and intratumorally heterogeneous access to therapies for breast tumors. It represents the first methodology of integrating CFD with patient specific MRI data for quantifying the spatiotemporally resolved drug propagation as well as the entire pressure and flow fields within the breast. NCI U01CA142565, U01CA CA174706, and R01 CA218700. CPRIT RR160005. Citation Format: Chengyue Wu, David A. Hormuth, Federico Pineda, Gregory S. Karczmar, Robert D. Moser, Thomas E. Yankeelov. Characterization of patient-specific drug delivery for breast cancer using image-guided computational fluid dynamics [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4263.

In simulations of partial differential equations using particle-in-cell (PIC) methods, it is often advantageous to resample the particle distribution function to increase simulation accuracy, reduce compute cost, and/or avoid numerical instabilities. We introduce an algorithm for particle resampling called Moment Preserving Contrained Resampling (MPCR). The general algorithm partitions the system space into smaller subsets and is designed to conserve any number of particle and grid quantities with a high degree of accuracy (i.e. machine accuracy). The resampling scheme can be integrated into any PIC code. The advantages of MPCR, including performance, accuracy, and stability, are presented by examining several numerical tests, including a use-case study in gyrokinetic fusion plasma simulations. The tests demonstrate that while the computational cost of MPCR is negligible compared to the nascent particle evolution in PIC methods, periodic particle resampling yields a significant improvement in the accuracy and stability of the results., 32 pages, 17 figures

Electron microscopy, chemical X-ray microanalysis, and Raman microscopy was used with expansion measurements of mortar bars in a systematic fashion to determine the impact of aggregate composition and exposure variations on alkali-silica reaction (ASR) products’ chemistry and structure. The results show that aggregate mineralogy plays a large role in the composition and structure of ASR products as does the local environment in which ASR products form. Additionally, solution exposure composition, a factor relevant to relating laboratory measurements to field performance, has a significant impact on ASR product chemistry but limited impact on structure, or at least on coordination of SiO2 in ASR products.

Background The human sulfatase 1 (SULF1) and sulfatase 2 (SULF2) genes modulate cell signaling and homeostasis in many tissues. Gene expression analyses have implicated SULF2 in disease pathogenesis, including Alzheimer's disease (AD), but changes in brain SULF2 expression have not been directly established. Objective To investigate the expression of SULF1 and SULF2 in brain tissues from AD cases and cognitively normal controls. Methods Autopsy tissue from AD cases (n = 20) and age-and gender-matched cognitively normal controls (n = 20) were identified from the Mayo Clinic Alzheimer's Disease Patient Registry neuropathology database. Tissue slides were stained for SULF1 and SULF2 protein expression in the hippocampus and frontal lobe and an expression score computed from the proportion of cells stained and the intensity of staining (range 0 [no expression] to 9 [marked expression]). Results SULF2 expression was reduced in AD cases. Compared to cognitively normal controls, SULF2 expression in AD cases was significantly decreased in the hippocampal Cornu Ammonis (CA) (mean score of 6.5 in cases versus 8.3 in controls; p = 0.003), in the gray matter of the parahippocampal gyrus (5.6 in cases versus 7.6 in controls; p = 0.003), and in the frontal lobe gray matter (5.4 in cases versus 7.4 in controls; p = 0.002). There was no difference in SULF1 expression in the hippocampus or frontal lobe of AD cases and controls. As expected there were no differences in SULF1 or SULF2 expression in white matter in AD cases compared to cognitively normal controls. Conclusion Decresed SULF2 in specific regions of the brain occurs in AD.

In this study, the effects of microstructural inclusions on fatigue life of polyether ether ketone (PEEK) was investigated. Due to the versatility of its material properties, the semi-crystralline PEEK polymer has been increasingly adopted in a wide range of applications particularly as a biomaterial for orthopedic, trauma, and spinal implants. To obtain the cyclic behavior of PEEK, uniaxial fully-reversed strain-controlled fatigue tests were conducted at ambient temperature and at 0.02 mm/mm to 0.04 mm/mm strain amplitudes. The microstructure of PEEK was obtained using the optical and the scanning electron microscope (SEM) to determine the microstructural inclusion properties in PEEK specimen such as inclusion size, type, and nearest neighbor distance. SEM analysis was also conducted on the fracture surface of fatigue specimens to observe microstructural inclusions that served as the crack incubation sites. Based on the experimental strain-life results and the observed microstructure of fatigue specimens, a microstructure-sensitive fatigue model was used to predict the fatigue life of PEEK that includes both crack incubation and small crack growth regimes. Results show that the employed model is applicable to capture microstructural effects on fatigue behavior of PEEK.

The discontinuous Petrov-Galerkin methodology with optimal test functions (DPG) of Demkowicz and Gopalakrishnan 18,20 guarantees the optimality of the solution in an energy norm, and provides several features facilitating adaptive schemes. Whereas Bubnov-Galerkin methods use identical trial and test spaces, Petrov-Galerkin methods allow these function spaces to differ. In DPG, test functions are computed on the fly and are chosen to realize the supremum in the inf-sup condition; the method is equivalent to a minimum residual method. For well-posed problems with sufficiently regular solutions, DPG can be shown to converge at optimal rates-the inf-sup constants governing the convergence are mesh-independent, and of the same order as those governing the continuous problem 48. DPG also provides an accurate mechanism for measuring the error, and this can be used to drive adaptive mesh refinements.We employ DPG to solve the steady incompressible Navier-Stokes equations in two dimensions, building on previous work on the Stokes equations, and focusing particularly on the usefulness of the approach for automatic adaptivity starting from a coarse mesh. We apply our approach to a manufactured solution due to Kovasznay as well as the lid-driven cavity flow, backward-facing step, and flow past a cylinder problems.

The increasing use of alternative cementitious materials such as geopolymers as an environmentally-friendly alternative to traditional cements requires an improved understanding of the interfacial transition zone (ITZ) between the matrix and reinforcing steels. In this study, nanoindentation measurements were spatially coupled to images with scanning electron microscopy and chemical composition using energy dispersive X-ray microanalysis. The study focused on the microstructure and chemical composition of the interfacial transition zone (ITZ) for reinforcing steel embedded in a geopolymer mortar. The ITZ was analyzed for uncoated steel and steel coated with a reactive porcelain enamel that improves bonding and corrosion resistance. Results indicate that a more gradual transition of mechanical properties and chemical composition for the coated steel coupled with improved integration to the mortar correlates to increased bond strength measured in macroscale experiments.

Genetic risk factors for cholangiocarcinoma (CCA) remain poorly understood. We assessed the effect of single-nucleotide polymorphisms (SNPs) of genes modulating inflammation or carcinogenesis on CCA risk and survival. We conducted a case-control, candidate gene association study of 370 CCA patients and 740 age-, sex-, and residential area-matched healthy controls. Eighteen functional or putatively functional SNPs in nine genes were genotyped. The log-additive genotype effects of SNPs on CCA risk and survival were determined using logistic regression and the log-rank test, respectively. Initial analysis identified significant associations between SNP rs2143417 and rs689466 in cyclooxygenase 2 (COX-2) and CCA risk, after adjusting for multiple comparisons (cutoff of P = 0.0028). However, these findings were not replicated in another independent cohort of 212 CCA cases and 424 matched controls. No significant association was found between any SNP and survival of CCA patients. Although COX-2 has been shown to contribute to cholangiocarcinogenesis, the COX-2 SNPs tested were not associated with risk of CCA. This study shows a lack of association between variants of genes related to inflammation and carcinogenesis and CCA risk and survival. Other factors than these genetic variants may play more important roles in CCA risk and survival.

A direct numerical simulation of incompressible channel flow at a friction Reynolds number ($\mathit{Re}_{{\it\tau}}$) of 5186 has been performed, and the flow exhibits a number of the characteristics of high-Reynolds-number wall-bounded turbulent flows. For example, a region where the mean velocity has a logarithmic variation is observed, with von Kármán constant ${\it\kappa}=0.384\pm 0.004$. There is also a logarithmic dependence of the variance of the spanwise velocity component, though not the streamwise component. A distinct separation of scales exists between the large outer-layer structures and small inner-layer structures. At intermediate distances from the wall, the one-dimensional spectrum of the streamwise velocity fluctuation in both the streamwise and spanwise directions exhibits $k^{-1}$ dependence over a short range in wavenumber $(k)$. Further, consistent with previous experimental observations, when these spectra are multiplied by $k$ (premultiplied spectra), they have a bimodal structure with local peaks located at wavenumbers on either side of the $k^{-1}$ range.

Background: Hepatocellular carcinoma (HCC) is the second most frequent cause of cancer death worldwide. Sulfatase 1 (SULF1) functions as a tumor suppressor in HCC cell lines in vitro but also has an oncogenic effect in some HCCs in vivo. Aim: The purpose of this study was to examine the mechanisms regulating SULF1 and its function in HCC. Methods: First, SULF1 mRNA and protein expression were examined. Second, we examined SULF1 gene copy numbers in HCC cells. Third, we assessed whether DNA methylation or methylation and/or acetylation of histone marks on the promoter regulate SULF1 expression. Finally, we examined the effect of 5-aza-2′-deoxycytidine (5-Aza-dC) on sulfatase activity and drug-induced apoptosis. Results: SULF1 mRNA was downregulated in nine of eleven HCC cell lines, but only in six of ten primary tumors. SULF1 mRNA correlated with protein expression. Gene copy number assessment by fluorescence in situ hybridization showed intact SULF1 alleles in low-SULF1-expressing cell lines. CpG island methylation in the SULF1 promoter and two downstream CpG islands did not show an inverse correlation between DNA methylation and SULF1 expression. However, chromatin immunoprecipitation showed that the SULF1 promoter acquires a silenced chromatin state in low-SULF1-expressing cells through an increase in di/trimethyl-K9H3 and trimethyl-K27H3 and a concomitant loss of activating acetyl K9, K14H3 marks. 5-Aza-dC restored SULF1 mRNA expression in SULF1-negative cell lines, with an associated increase in sulfatase activity and sensitization of HCC cells to cisplatin-induced apoptosis. Conclusion: SULF1 gene silencing in HCC occurs through histone modifications on the SULF1 promoter. Restoration of SULF1 mRNA expression by 5-Aza-dC sensitized HCC cells to drug-induced apoptosis.

„Cyclic alternating pattern“ (CAP) stellen eine periodische Aktivitat des „Non-rapid-eye-movement“(NREM)-Schlafs im Elektroenzephalogramm (EEG) dar. Sie sind durch Sequenzen transienter elektrokortikaler Ereignisse gekennzeichnet, unterscheiden sich von der EEG-Hintergrundaktivitat durch Frequenz- und/oder Amplitudenanderung und treten in regelmasigen Intervallen auf. In mehreren Studien konnte bestatigt werden, dass CAP sowohl bei Schlafgesunden als auch im Rahmen von Schlafstorungen vorkommen konnen. Als Indikator fur die Instabilitat des Schlafprozesses ermoglicht die CAP-Analyse einen objektiven Zugang, um die Schlafqualitat zu bewerten.

A multifaceted exploration of the NASA Langley Research Center Multidisciplinary Uncertainty Quantification Challenge Problem aimed at examining the suitability of a probabilistic characterization of the epistemic uncertainties included with the problem statement is pursued. In the process, subproblems A through D are treated, and the opportunities and challenges associated with a probabilistic description are delineated as they pertain to each uncertainty characterization, uncertainty propagation, and uncertainty management, as well as to sensitivity analysis. All epistemic variables are replaced with random variables, and an equivalent effective uncertainty model with no epistemic component is identified. A Bayesian approach for parameter inference and an update that is applied directly on the probability densities of the various uncertainty variables are pursued, and sampling techniques for uncertainty propagation are used. A conditional expectation approach and a method based on the reduction of epist...

Lyapunov exponents measure the average exponential growth rate of typical linear perturbations in a chaotic system, and the inverse of the largest exponent is a measure of the time horizon over which the evolution of the system can be predicted. Here, Lyapunov exponents are determined in forced homogeneous isotropic turbulence for a range of Reynolds numbers. Results show that the maximum exponent increases with Reynolds number faster than the inverse Kolmogorov time scale, suggesting that the instability processes may be acting on length and time scales smaller than Kolmogorov scales. Analysis of the linear disturbance used to compute the Lyapunov exponent, and its instantaneous growth, show that the instabilities do, as expected, act on the smallest eddies, and that at any time, there are many sites of local instabilities.

Graphene oxide (GO) has emerged as a promising material for next-generation water treatment membranes. In this study, three types of GO membranes were produced and tested. Both GO and graph...

Profiles of $\ensuremath{\langle}p\phantom{\rule{0}{0ex}}p{\ensuremath{\rangle}}^{+}$ from direct numerical simulation calculations are correlated for various Reynolds numbers. The correlating functions are unusual; a single function in the outer region and a defect function in the inner region. This is exactly opposite of the correlating functions for the mean velocity.

Severe cracking has been observed on the miter gate anchorages at Chickamauga Lock, Nashville District, U.S. Army Corps of Engineers. A structural analysis of these anchorages was conducted to determine how much longer they could remain in service before failure is expected. This analysis included a review of existing structural analysis reports, estimates and prediction of observed concrete growth in the area near the anchorages, and fatigue life estimates. The fatigue life estimates included the concrete growth estimates and also included the stresses and strains taken from measurements recorded during miter gate movements during lockages. The results of this analysis are discussed as well as possible ways to extend the life of the existing anchorages and considerations for if and when the anchorages are replaced.

Results of a recent joint experimental and computational investigation of the flow through a plenum-fed 7-7-7 shaped film cooling hole are presented. In particular, we compare the measured adiabatic effectiveness and mean temperature against implicit large eddy simulation (iLES) for blowing ratio approximately 2, density ratio 1.6, and Reynolds number 6000. The results overall show reasonable agreement between the iLES and the experimental results for the adiabatic effectiveness and gross features of the mean temperature field. Notable discrepancies include the centerline adiabatic effectiveness near the hole, where the iLES under-predicts the measurements by Δη ≈ 0.05, and the near-wall temperature, where the simulation results show features not present in the measurements. After showing this comparison, the iLES results are used to examine features that were not measured in the experiments, including the in-hole flow and the dominant fluxes in the mean internal energy equation downstream of the hole. Key findings include that the flow near the entrance to the hole is highly turbulent and that there is a large region of backflow near the exit of the hole. Further, the well-known counter-rotating vortex pair downstream of the hole is observed. Finally, the typical gradient diffusion hypothesis for the Reynolds heat flux is evaluated and found to be incorrect.

A new slow growth formulation for DNS of wall-bounded turbulent flow is developed and demonstrated to enable extension of slow growth modeling concepts to complex boundary layer flows. As in previous slow growth approaches, the formulation assumes scale separation between the fast scales of turbulence and the slow evolution of statistics such as the mean flow. This separation enables the development of approaches where the fast scales of turbulence are directly simulated while the forcing provided by the slow evolution is modeled. The resulting model admits periodic boundary conditions in the streamwise direction, which avoids the need for extremely long domains and complex inflow conditions that typically accompany spatially developing simulations. Further, it enables the use of efficient Fourier numerics. Unlike previous approaches, the present approach is based on a temporally evolving boundary layer and is specifically tailored to give results for calibration and validation of RANS turbulence models. The use of a temporal homogenization simplifies the modeling, enabling straightforward extension to flows with complicating features, including cold and blowing walls. To generate data useful for calibration and validation of RANS models, special care is taken to ensure that the mean slow growth forcing is closed in terms of the mean and other quantities that appear in standard RANS models, ensuring that there is no confounding between typical RANS closures and additional closures required for the slow growth problem. The performance of the method is demonstrated on two problems: an essentially incompressible, zero-pressure-gradient boundary layer and a transonic boundary layer over a cooled wall with wall transpiration.

Context.The mechanism of disk formation around fast-rotating Be stars is not well understood. In particular, it is not clear which mechanisms operate, in addition to fast rotation, to produce the observed variable ejection of matter. The star Achernar is a privileged laboratory to probe these additional mechanisms because it is close, presents B ⇌ Be phase variations on timescales ranging from ~6 yr to ~15 yr, a companion star was discovered around it, and probably presents a polar wind or jet.Aims.Despite all these previous studies, the disk around Achernar was never directly imaged. Therefore we seek to produce an image of the photosphere and close environment of the star.Methods.We used infrared long-baseline interferometry with the PIONIER instrument at the Very Large Telescope Interferometer (VLTI) to produce reconstructed images of the photosphere and close environment of the star over four years of observations. To study the disk formation, we compared the observations and reconstructed images to previously computed models of both the stellar photosphere alone (normal B phase) and the star presenting a circumstellar disk (Be phase).Results.The observations taken in 2011 and 2012, during the quiescent phase of Achernar, do not exhibit a disk at the detection limit of the instrument. In 2014, on the other hand, a disk was already formed and our reconstructed image reveals an extendedH-band continuum excess flux. Our results from interferometric imaging are also supported by several Hαline profiles showing that Achernar started an emission-line phase sometime in the beginning of 2013. The analysis of our reconstructed images shows that the 2014 near-IR flux extends to ~1.7–2.3 equatorial radii. Our model-independent size estimation of theH-band continuum contribution is compatible with the presence of a circumstellar disk, which is in good agreement with predictions from Be-disk models.

Existing antiangiogenic approaches to treat metastatic hepatocellular carcinoma (HCC) are weakly effectual, prompting further study of tumor angiogenesis in this disease setting. Here, we report a novel role for sulfatase 2 (SULF2) in driving HCC angiogenesis. Sulf2-deficient mice (Sulf2 KO) exhibited resistance to diethylnitrosamine-induced HCC and did not develop metastases like wild-type mice (Sulf2 WT). The smaller and less numerous tumors formed in Sulf2 KO mice exhibited a markedly lower microvascular density. In human HCC cells, SULF2 overexpression increased endothelial proliferation, adhesion, chemotaxis, and tube formation in a paracrine fashion. Mechanistic analyses identified the extracellular matrix protein periostin (POSTN), a ligand of avb3/5 integrins, as an effector protein in SULF2-induced angiogenesis. POSTN silencing in HCC cells attenuated SULF2-induced angiogenesis and tumor growth in vivo. The TGFb1/SMAD pathway was identified as a critical signaling axis between SULF2 and upregulation of POSTN transcription. In clinical HCC specimens, elevated levels of SULF2 correlated with increased microvascular density, POSTN levels, and relatively poorer patient survival. Together, our findings define an important axis controlling angiogenesis in HCC and a mechanistic foundation for rational drug development. Fil: Chen, Gang. Mayo Clinic; Estados Unidos. Wenzhou Medical University; China Fil: Nakamura, Ikuo. Mayo Clinic; Estados Unidos Fil: Dhanasekaran, Renumathy. Mayo Clinic; Estados Unidos. University of Stanford; Estados Unidos Fil: Iguchi, Eriko. Schulze Center For Novel Therapeutics, Mayo Clinic; Estados Unidos Fil: Tolosa, Ezequiel Julian. Schulze Center For Novel Therapeutics, Mayo Clinic; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentina Fil: Romecin, Paola A.. Schulze Center For Novel Therapeutics, Mayo Clinic; Estados Unidos Fil: Vera, Renzo Emanuel. Schulze Center For Novel Therapeutics, Mayo Clinic; Estados Unidos. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Departamento de Biología Molecular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina Fil: Almada, Luciana Victoria. Schulze Center For Novel Therapeutics, Mayo Clinic; Estados Unidos Fil: Miamen, Alexander G.. Mayo Clinic; Estados Unidos Fil: Chaiteerakij, Roongruedee. Mayo Clinic; Estados Unidos Fil: Zhou, Mengtao. Wenzhou Medical University; China Fil: Asiedu, Michael K.. Mayo Clinic; Estados Unidos Fil: Moser, Catherine D.. Mayo Clinic; Estados Unidos Fil: Han, Shaoshan. Mayo Clinic; Estados Unidos Fil: Hu, Chunling. Mayo Clinic; Estados Unidos Fil: Banini, Bubu A.. Mayo Clinic; Estados Unidos Fil: Oseini, Abdul M.. Mayo Clinic; Estados Unidos Fil: Chen, Yichun. Mayo Clinic; Estados Unidos Fil: Fang, Yong. Mayo Clinic; Estados Unidos Fil: Yang, Dongye. Mayo Clinic; Estados Unidos Fil: Shaleh, Hassan M.. Mayo Clinic; Estados Unidos Fil: Wang, Shaoqing. Mayo Clinic; Estados Unidos Fil: Wu, Dehai. Mayo Clinic; Estados Unidos Fil: Song, Tao. Mayo Clinic; Estados Unidos Fil: Lee, Ju-Seog. Anderson Cancer Center; Estados Unidos Fil: Thorgeirsson, Snorri S.. National Cancer Institute; Estados Unidos Fil: Chevet, Eric. Université Rennes; Francia Fil: Shah, Vijay H.. Mayo Clinic; Estados Unidos Fil: Fernandez-Zapico, Martin E.. Schulze Center For Novel Therapeutics, Mayo Clinic; Estados Unidos Fil: Roberts, Lewis R.. Mayo Clinic; Estados Unidos

33rd European Photovoltaic Solar Energy Conference and Exhibition; 2917-2920, The service life estimation in the photovoltaic (PV) industry is yet in its infancy, requiring both underpinning science and trained personnel to reduce costs of energy. An unmet industrial requirement is an accelerated and operating environment specific, service life time and energy yield assessment. SOLAR-TRAIN qualifies early stage researchers (ESRs) in the field of PV durability as part of a highly innovative, multi-disciplinary project meeting industry requirements. The research objective is to develop novel and validated models for the service life time and energy prediction of PV modules and systems. The elements to this puzzle are researched in the frame of 14 PhD projects with individual areas of focus, ranging from investigations on climatic degradation factors, through to research on material level, simulations and modelling of energy yield and life time. The research projects are enhanced by an innovative training scheme in close cooperation with industry. This inter-sectoral approach provides excellent theoretical and technical background as well as immersion in different business sectors and career mentoring.

Biomineralization in crustaceans is a remarkably efficient process of ion transport and phase transformation in a spatial template. Here we show the use of this preorganized pathway with waste shrimp shell as both a phosphate source and template for the mineralization of UO22+ to uramphite. By using the physical structural and chemical reservoir of the biogenic platform, the only requirement was to develop a solution for ion supply. Hydroxylammonium acetate, an amphiprotic salt parallel to the amine and carboxylic acid motif pervasive in biomolecules, was prepared and used for the delivery of dissolved uranyl ions into the spatial constraints of the exoskeleton. Although biomediated phase transformations of exogenous metals is typically limited to living organisms, our results show that metabolically inactive shrimp shells are adaptive and responsive toward a nonessential ion. This suggests the nonliving exoskeleton may provide rapid bottom-up assembly routes to technologically important new inorganic cry...

In this study we provide the first comprehensive assessment of the environmental and anthropogenic factors driving bryophyte invasions worldwide. We compiled data of alien bryophyte distributions from 82 regions on five continents and oceanic islands and region specific variables. For each species, we collected data on its region-specific invasion stage, i.e. casual (ephemeral) vs naturalized (persistent) occurrences, and we differentiated between known aliens and those which are likely to be alien (cryptogenic). We used these data to test how species attributes, environmental and socio-economic conditions of the study areas as well as introduction effort affect invasion probabilities at different invasion stages and of known alien vs cryptogenic species. We collected information on species’ attributes (native range size and location, niche breadth, habitat affiliation), and calculated variables characterising the environmental, biogeographic and socio-economic features of the native and recepient regions. Subsequently, we related the probability of alien occurrence across different invasion stages with these species- and region-wise predictor variables using generalized linear mixed effects models. Greater native range size raised the likelihood that a species becomes alien or cryptogenic. Islands are more invaded by alien (and cryptogenic) bryophytes than continental regions. Native range size and socio-economic activity increase the likelihood that a species becomes alien or cryptogenic elsewhere. Interestingly, among alien bryophytes naturalizations occur more frequently in regions of the complementary hemisphere than in regions of their native hemisphere. In general, regions in the Southern Hemisphere have higher numbers of naturalized bryophytes. We conclude that there is a conspicuous change in factors determining bryophyte invasions at different invasion stages. Whereas alien and cryptogenic bryophyte species occurrences are more frequent on islands and depend on native range size, and hence probably propagule pressure, naturalized bryophytes are more frequent in areas which are biogeographically separated but climatically similar to the native ranges.

We performed a direct numerical simulation (DNS) of high Reynolds number turbulent channel flow to expand our understanding of wall-bounded turbulence. The resolution requirements inherent to realistic turbulent flows necessitate leadership computing systems. Using Mira at Argonne Leadership Computing Facility, Argonne National Laboratory, we were able to achieve DNS at Re_tau = 5,200, and generated approximately 140 Tbytes of data. To use Mira efficiently, we developed a new DNS code, PoongBack, including a new parallel 3D FFT kernel. The new code shows excellent scalability up to 786,432 cores. Here, we summarize our code development and production simulation efforts, including parallel I/O.

Novel diagnostic techniques incorporating focused ion beam (FIB) micro-milling, scanning electron microscopy (SEM), and in-situ SEM nanomechanical load frames performed micro-cantilever beam experiments on bio-inspired nanocomposites. Video of fracture behavior during the experiments correlated to load frame data indicated a hardening mechanism similar to the deformation mechanisms found in nacre. These methods developed for nanocomposites are applicable to a wide range of material systems for providing a unique understanding of deformation and failure mechanisms at lower length scales.

The Discontinuous Petrov–Galerkin (DPG) method is a class of novel higher order adaptive finite element methods derived from the minimization of the residual of the variational problem (Demkowicz and Gopalakrishnan, 2011) [1], and has been shown to deliver a method for convection–diffusion that is provably robust in the diffusion parameter (Demkowicz and Heuer, in press; Chan et al., in press) [2,3]. In this work, the DPG method is extrapolated to nonlinear systems, and applied to several problems in fluid dynamics whose solutions exhibit boundary layers or singularities in stresses. In particular, the effectiveness of DPG as a numerical method for compressible flow is assessed with the application of DPG to two model problems over a range of Mach numbers and laminar Reynolds numbers using automatic adaptivity with higher order finite elements, beginning with highly under-resolved coarse initial meshes.

This research focused on improving ultra high-performance concrete (UHPC) toughness through the addition of annealed plain carbon steel fibers and stainless steel fibers that both exhibit increased ductility and strain hardening compared with conventional steel fibers used for concrete reinforcement. Implementing optimized heat treatments and selecting proper alternative alloys can improve the postyield carrying capacity of UHPCs through plastic deformations, phase transformations, and fiber pullout. This research focused on the flexural response and dynamic penetration resistance of a UHPC known as Cor-Tuf with three different steel fiber types: plain carbon steel, stainless steel that can exhibit phase transformation-induced plasticity, and annealed carbon steel with reduced tensile strength but increased ductility and strain hardening. Annealed carbon steel fibers were able to reduce mass loss by 0.8 % for 5-cm-thick dynamic impact panels. By using a phase-transformable stainless steel, the ultimate flexural strength increased from 32.0 to 42.5 MPa (33 % increase) and the postimpact velocity decreased an average of 31.5 m/s for 2.5 and 5-cm-thick dynamic impact panels. Phase transformations (austenitic to martensitic) were quantified in the stainless steel fibers of postyielded UHPC specimens using a vibrating sample magnetometer. Stainless steel fibers sampled from the postyielded tensile face of a flexural beam increased from 75 to 107 emu/g. The results of the study evidence improvements in tensile properties and toughness that can be accomplished by modifying the stress versus strain response of steel fiber reinforcement and including new energy dissipation mechanisms such as phase transformation.

Accumulation of carbonaceous deposits (also known industrially as “coke”) on catalytic active sites derived from process conditions has been a long-standing problem in industrial catalysis. Over accumulation of the deposits ultimately lead to deactivation; thus, characterization of coke evolution becomes critical toward developing catalytic materials with improved stability. This study focuses on extending an understanding of how and where coke forms on Pt–Re/γ-Al2O3, an industrial catalyst used in reforming processes. With the use of spherical aberration-corrected scanning transmission electron microscopy (Cs-STEM) and enhanced energy dispersive X-ray spectroscopy (EDX), we characterize the Pt–Re metal sites and show, to our knowledge, the first examples of chemically imaged subnanometer particles and also the first to use chemical maps to identify coke location on a catalyst. A two-step mechanism is reported based on the results whereby coke appears to stream from the metal function of the catalyst resu...

This study examines the effectiveness of a reactive vitreous enamel coating on the surface of reinforcing steel on bond strengths and microstructural interactions with a geopolymer-based binder. Steel rods with and without the glassy enamel coating rich in Al, Si, and Ca were tested for bond strength when embedded in a Class F fly ash geopolymer. Microstructural characterization using scanning electron microscopy and energy-dispersive X-ray spectroscopy was also used to investigate the spatial distribution in microstructure and chemistry at the interface. The use of a reactive enamel coating on reinforcement was found to increase bond strengths by approximately 2.5 times based on push-out test specimens. The presence of the reactive enamel coating was found to decrease porosity at the interface and also provide a more gradual transition in microstructure and chemistry between the steel reinforcement and the geopolymeric matrix. Results of the study support investigation of the developed coating system for reinforcing bars, fibers, and stay-in-place formwork systems.

Little work has been done to study the fundamental material behaviors and failure mechanisms of cement-based materials including ordinary Portland cement concrete and ultra-high performance concretes (UHPCs) under high strain impact and penetration loads at lower length scales. These high strain rate loadings have many possible effects on UHPCs at the microscale and nanoscale, including alterations in the hydration state and bonding present in phases such as calcium silicate hydrate, in addition to fracture and debonding. In this work, the possible chemical and physical changes in UHPCs subjected to high strain rate impact and penetration loads were investigated using a novel technique wherein nanoindentation measurements were spatially correlated with images using scanning electron microscopy and chemical composition using energy dispersive x-ray microanalysis. Results indicate that impact degrades both the elastic modulus and indentation hardness of UHPCs, and in particular hydrated phases, with damage likely occurring due to microfracturing and debonding.

Synthetic jet actuators are investigated for rapidly maneuvering airfoils that are regulated by a closed-loop control system. To support active flow-control simulations performed here, the closed-loop system and vehicle dynamics are coupled with computational fluid dynamics. High-frequency sinusoidal pitching simulations with and without synthetic jet actuation indicate that the current synthetic jet actuators provide bidirectional change in aerodynamic forces during rapid maneuvers whose time scales are of the same order as the flow time scales. Responses of a wind-tunnel airfoil are well represented in the current simulations, which allows us to predict the response of the system for dynamic conditions representative of free flight. The control system is able to execute rapid free-flight maneuvers. It is observed that the controller is responding to small fluctuations caused by vortex shedding from the trailing-edge actuators.

Tissue regeneration requires the activation of a set of specific growth signaling pathways. The identity of these cascades and their biological roles are known; however, the molecular mechanisms regulating the interplay between these pathways remain poorly understood. Here, we define a new role for SULFATASE 2 (SULF2) in regulating tissue regeneration and define the WNT-GLI1 axis as a novel downstream effector for this sulfatase in a liver model of tissue regeneration. SULF2 is a heparan sulfate 6-O-endosulfatase, which releases growth factors from extracellular storage sites turning active multiple signaling pathways. We demonstrate that SULF2-KO mice display delayed regeneration after partial hepatectomy (PH). Mechanistic analysis of the SULF2-KO phenotype showed a decrease in WNT signaling pathway activity in vivo. In isolated hepatocytes, SULF2 deficiency blocked WNT-induced β-CATENIN nuclear translocation, TCF activation, and proliferation. Furthermore, we identified the transcription factor GLI1 as a novel target of the SULF2-WNT cascade. WNT induces GLI1 expression in a SULF2- and β-CATENIN-dependent manner. GLI1-KO mice phenocopied the SULF2-KO, showing delayed regeneration and decreased hepatocyte proliferation. Moreover, we identified CYCLIN D1, a key mediator of cell growth during tissue regeneration, as a GLI1 transcriptional target. GLI1 binds to the cyclin d1 promoter and regulates its activity and expression. Finally, restoring GLI1 expression in the liver of SULF2-KO mice after PH rescues CYCLIN D1 expression and hepatocyte proliferation to wild-type levels. Thus, together these findings define a novel pathway in which SULF2 regulates tissue regeneration in part via the activation of a novel WNT-GLI1-CYCLIN D1 pathway.

Materials such as bone, nacre, and fish scales have unique structures that give the material strength as well as ductility. The ultimate goal of our research is to develop new composite materials that have improved strength and ductility compared to conventional materials. The US Army Engineer Research and Development Center is incorporating these design principles to develop hierarchical materials for structural applications. In the present study, the mineralogy and morphology of calcium-containing carbonates precipitated by reacting (NH4)2CO3 with mixed Ca, Sr, Mg, and Mn-acetates was investigated. As the proportion of the non-Ca component increased, the products shifted toward double carbonates and mixtures of double carbonates with single carbonates. Characterization by scanning electron microscopy and X-ray diffraction to determine crystal sizes, morphology, and structure of precipitated phases indicated a potential for re-crystallizing the products to form new composite materials. Ongoing research efforts are focused on using information obtained in the present study to develop composites by hydrothermal recrystallization of metastable phases.

During recent decades, research on biological systems such as abalone shell and fish armor has revealed that these biological systems employ carefully arranged hierarchical multilayered structures to achieve properties of high strength, high ductility and light weight. Knowledge of such structures may enable pathways to design bio-inspired materials for various applications. This study was conducted to investigate the spatial distribution of structure, chemical composition and mechanical properties in mineralized fish scales of the species Atractosteus spatula. Microindentation tests were conducted, and cracking patterns and damage sites in the scales were examined to investigate the underlying protective mechanisms of fish scales under impact and penetration loads. A difference in nanomechanical properties was observed, with a thinner, stiffer and harder outer layer (indentation modulus ∼69 GPa and hardness ∼3.3 GPa) on a more compliant and thicker inner layer (indentation modulus ∼14.3 GPa and hardness ∼0.5 GPa). High-resolution scanning electron microscopy imaging of a fracture surface revealed that the outer layer contained oriented nanorods embedded in a matrix, and that the nanostructure of the inner layer contained fiber-like structures organized in a complex layered pattern. Damage patterns formed during microindentation show complex deformation mechanisms. Images of cracks identify growth through the outer layer, then deflection along the interface before growing and arresting in the inner layer. High-magnification images of the crack tip in the inner layer show void-linking and fiber-bridging exhibiting inelastic behavior. The observed difference in mechanical properties and unique nanostructures of different layers may have contributed to the resistance of fish scales to failure by impact and penetration loading.

Within the framework of the Multidisciplinary Experimental and Modeling Impact Research Network (MEMIN) research group, the damage zones underneath two experimentally produced impact craters in sandstone targets were investigated using several nondestructive testing (NDT) methods. The 20 · 20 · 20 cm sandstones were impacted by steel projectiles with a radius of 1.25 mm at approximately 5 km s)1, resulting in craters with approximately 6 cm diameter and approximately 1 cm depth. Ultrasound (US) tomography and vibrational analysis were applied before and after the impact experiments to characterize the damage zone, and micro-computer tomography (l-CT) measurements were performed to visualize subsurface fractures. The newly obtained experimental data can help to quantify the extent of the damage zone, which extends to about 8 cm depth in the target. The impacted sandstone shows a local p-wave reduction of 18% below the crater floor, and a general reduction in elastic moduli by between approximately 9 and approximately 18%, depending on the type of elastic modulus. The results contribute to a better empirical and theoretical understanding of hypervelocity events and simulations of cratering processes.